Nichols (2006) compiled some common clinical issues: countertransference, non-disclosure, coming-out, partner/families, and bleed-through.

Countertransference is a common problem in clinical settings. Despite having no evidence, therapists may find themselves believing that their client’s pathology is "self-evident". Therapists may feel intense disgust and aversive reactions. Feelings of countertransference can interfere with therapy. Another common problem is when clients conceal their sexual preferences from their therapists. This can compromise any therapy. To avoid non-disclosure, therapists are encouraged to communicate their openness in indirect ways with literatures and artworks in the waiting room. Therapists can also deliberately bring up BDSM topics during the course of therapy. With less informed therapists, sometimes they over-focus on clients’ sexuality which detracts from original issues such as family relationships, depression, etc. A special subgroup that needs counselling is the "newbie". Individuals just coming out might have internalized shame, fear, and self-hatred about their sexual preferences. Therapists need to provide acceptance, care, and model positive attitude; providing reassurance, psychoeducation, and bibliotherapy for these clients is crucial. The average age when BDSM individuals realize their sexual preference is around 26 years. Many people hide their sexuality until they can no longer contain their desires. However, they may have married or had children by this point. Therefore, therapists need to facilitate couple's counselling and disclosure. It is important for therapists to consider fairness to partner and family of clients. In situations when boundaries between roles in the bedroom and roles in the rest of the relationship blurs, a "bleed-through" problem has occurred. Therapists need to help clients resolve distress and deal with any underlying problems that led to the initial bleed-through.

Polycephaly is the condition of having more than one head. The term is derived from the Egyptian stems "poly" (Greek: "πολύ") meaning "many" and "kephalē" (Greek: "κεφάλη") meaning "head". A polycephalic organism may be thought of as one being with a supernumerary body part, or as two or more beings with a shared body.

Two-headed animals (called bicephalic or dicephalic) and three-headed (tricephalic) animals are the only type of multi-headed creatures seen in the real world, and form by the same process as conjoined twins from monozygotic twin embryos.

In humans, there are two forms of twinning that can lead to two heads being supported by a single torso. In dicephalus parapagus dipus, the two heads are side by side. In craniopagus parasiticus, the two heads are joined directly to each other, but only one head has a functional torso. Survival to adulthood is rare, but does occur in some forms of dicephalus parapagus dipus.

There are many occurrences of multi-headed animals in mythology. In heraldry and vexillology, the double-headed eagle is a common symbol, though no such animal is known to have ever existed.

Some types of BDSM play include, but are not limited to:

- Animal roleplay

- Bondage

- Breast torture

- Cock and ball torture (CBT)

- Erotic electrostimulation

- Edgeplay

- Flogging

- Golden showers (urinating)

- Human furniture

- Japanese bondage

- Medical play

- Paraphilic infantilism

- Predicament bondage

- Pussy torture

- Sexual roleplay

- Spanking

- Suspension

- Torture

- Tickle torture

- Wax play

Two-headed people and animals, though rare, have long been known to exist and documented.

Foot binding was the custom of applying tight binding to the feet of young girls to modify the shape of their feet. The practice possibly originated among upper class court dancers during the Five Dynasties and Ten Kingdoms period in 10th century China, then became popular among the elite during the Song dynasty and eventually spread to all social classes by the Qing dynasty. Foot binding became popular as a means of displaying status (women from wealthy families, who did not need their feet to work, could afford to have them bound) and was correspondingly adopted as a symbol of beauty in Chinese culture. Foot binding limited the mobility of women, resulting in them walking in a swaying unsteady gait, although some women with bound feet working outdoor had also been reported. The prevalence and practice of foot binding varied in different parts of the country. Feet altered by binding were called lotus feet.

It has been estimated that by the 19th century, 40–50% of all Chinese women may have had bound feet, and up to almost 100% among upper class Han Chinese women. The Manchu Kangxi Emperor tried to ban foot binding in 1664 but failed. In the later part of the 19th century, Chinese reformers challenged the practice but it was not until the early 20th century that foot binding began to die out as a result of anti-foot-binding campaigns. Foot-binding resulted in lifelong disabilities for most of its subjects, and a few elderly Chinese women still survive today with disabilities related to their bound feet.

In Chinese alchemy, elixir poisoning refers to the toxic effects from elixirs of immortality that contained metals and minerals such as mercury and arsenic. The official "Twenty-Four Histories" record numerous Chinese emperors, nobles, and officials who ironically died from taking elixirs in order to prolong their lifespans. The first emperor to die from elixir poisoning was likely Qin Shi Huang (d. 210 BCE) and the last was Yongzheng (d. 1735). Despite common knowledge that immortality potions could be deadly, fangshi and Daoist alchemists continued the elixir-making practice for two millennia.

The process was started before the arch of the foot had a chance to develop fully, usually between the ages of 4 and 9. Binding usually started during the winter months since the feet were more likely to be numb, and therefore the pain would not be as extreme.

First, each foot would be soaked in a warm mixture of herbs and animal blood; this was intended to soften the foot and aid the binding. Then, the toenails were cut back as far as possible to prevent in-growth and subsequent infections, since the toes were to be pressed tightly into the sole of the foot. Cotton bandages, 3 m long and 5 cm wide (10 ft by 2 in), were prepared by soaking them in the blood and herb mixture. To enable the size of the feet to be reduced, the toes on each foot were curled under, then pressed with great force downwards and squeezed into the sole of the foot until the toes broke.

The broken toes were held tightly against the sole of the foot while the foot was then drawn down straight with the leg and the arch of the foot was forcibly broken. The bandages were repeatedly wound in a figure-eight movement, starting at the inside of the foot at the instep, then carried over the toes, under the foot, and around the heel, the freshly broken toes being pressed tightly into the sole of the foot. At each pass around the foot, the binding cloth was tightened, pulling the ball of the foot and the heel together, causing the broken foot to fold at the arch, and pressing the toes underneath the sole. The binding was pulled so tightly that the girl could not move her toes at all and the ends of the binding cloth were then sewn so that the girl could not loosen it.

The girl's broken feet required a great deal of care and attention, and they would be unbound regularly. Each time the feet were unbound, they were washed, the toes carefully checked for injury, and the nails carefully and meticulously trimmed. When unbound, the broken feet were also kneaded to soften them and the soles of the girl's feet were often beaten to make the joints and broken bones more flexible. The feet were also soaked in a concoction that caused any necrotic flesh to fall off.

Immediately after this agonizing procedure, the girl's broken toes were folded back under and the feet were rebound. The bindings were pulled even tighter each time the girl's feet were rebound. This unbinding and rebinding ritual was repeated as often as possible (for the rich at least once daily, for poor peasants two or three times a week), with fresh bindings. It was generally an elder female member of the girl's family or a professional foot binder who carried out the initial breaking and ongoing binding of the feet. It was considered preferable to have someone other than the mother do it, as she might have been sympathetic to her daughter's pain and less willing to keep the bindings tight.

For most the bound feet eventually became numb. However, once a foot had been crushed and bound, attempting to reverse the process by unbinding is painful, and the shape could not be reversed without a woman undergoing the same pain all over again.

Poena cullei (from Latin 'penalty of the sack') under Roman law was a type of death penalty imposed on a subject who had been found guilty of parricide. The punishment consisted of being sewn up in a leather sack, sometimes with an assortment of live animals, and then being thrown into water. The punishment may have varied widely in its frequency and precise form during the Roman period. For example, the earliest fully documented case is from ca. 100 BCE, although scholars think the punishment may have developed about a century earlier (earlier than that, murderers, including parricides, would be handed over to the aggrieved family for punishment, rather than punishment being enacted by Roman state officials). Inclusion of live animals in the sack is only documented from Early Imperial times, and at the beginning, only snakes are mentioned. At the time of Emperor Hadrian (2nd century CE), the most well known form of the punishment was documented, where a cock, a dog, a monkey and a viper were inserted in the sack. However, at the time of Hadrian "poena cullei" was made into an optional form of punishment for parricides (the alternate being thrown to the beasts in the arena). During the 3rd century CE up to the accession of Emperor Constantine, "poena cullei" fell out of use; Constantine revived it, now with only serpents to be added in the sack. Well over 200 years later, Emperor Justinian reinstituted the punishment with the four animals, and "poena cullei" remained the statutory penalty for parricides within Byzantine law for the next 400 years, when it was replaced with the punishment for parricides to be burnt alive instead.

"Poena cullei" gained a revival of sorts in late medieval and early modern Germany, with late cases of being drowned in a sack along with live animals being documented from Saxony in the first half of the 18th century.

The etymology of English elixir derives from Medieval Latin "", from Arabic ("al-ʾiksīr"), probably from Ancient Greek ("xḗrion" "a desiccative powder for wounds"). "Elixir" originated in medieval European alchemy meaning "A preparation by the use of which it was sought to change metals into gold" (elixir stone or philosopher's stone) or "A supposed drug or essence with the property of indefinitely prolonging life" (elixir of life). The word was figuratively extended to mean "A sovereign remedy for disease. Hence adopted as a name for quack medicines" (e.g., Daffy's Elixir) and "The quintessence or soul of a thing; its kernel or secret principle". In modern usage, "elixir" is a pharmaceutical term for "A sweetened aromatic solution of alcohol and water, serving as a vehicle for medicine" ("Oxford English Dictionary", 2nd ed., 2009). Outside of Chinese cultural contexts, English "elixir poisoning" usually refers to accidental contamination, such as the 1937 Elixir sulfanilamide mass poisoning in the United States.

"Dān" 丹 "cinnabar; vermillion; elixir; alchemy" is the keyword for Chinese immortality elixirs. The red mineral cinnabar ("dānshā" 丹砂 lit. "cinnabar sand") was anciently used to produce the pigment vermilion ("zhūhóng" 朱紅) and the element mercury ("shuǐyín" 水銀 "watery silver" or "gǒng" 汞).

According to the "ABC Etymological Dictionary of Old Chinese", the etymology of Modern Standard Chinese "dān" from Old Chinese "*tān" (< *"tlan" ?) 丹 "red; vermillion; cinnabar", "gān" 矸 in "dāngān" 丹矸 from *"tân-kân" (< *"tlan-klan" ?) "cinnabar; vermillion ore", and "zhān" from *"tan" 旃 "a red flag" derive from Proto-Kam-Sui *"h-lan" "red" or Proto-Sino-Tibetan *"tja-n" or *"tya-n" "red". The *"t-" initial and *"t-" or *"k-" doublets indicate that Old Chinese borrowed this item. (Schuessler 2007: 204).

Although the word "dan" 丹 "cinnabar; red" frequently occurs in oracle script from the late Shang Dynasty (ca. 1600-1046 BCE) and bronzeware script and seal script from the Zhou Dynasty (1045-256 BCE), paleographers disagree about the graphic origins of the logograph 丹 and its ancient variants 𠁿 and 𠕑. Early scripts combine a 丶 dot or ⼀ stroke (depicting a piece of cinnabar) in the middle of a surrounding frame, which is said to represent:

- "jǐng" 井 "well" represents the mine from which the cinnabar is taken" ("Shuowen Jiezi")

- "the crucible of the Taoist alchemists" (Léon Wieger )

- "the contents of a square receptacle" (Bernhard Karlgren)

- "placed in a tray or palette to be used as red pigment" (Wang Hongyuan 王宏源)

- "mineral powder on a stretched filter-cloth" (Needham and Lu).

Many Chinese elixir names are compounds of "dan", such as "jīndān" 金丹 (with "gold") meaning "golden elixir; elixir of immortality; potable gold" and "xiāndān" 仙丹 (with "Daoist immortal") "elixir of immortality; panacea", and "shéndān" 神丹 (with "spirit; god") "divine elixir". "Bùsǐ zhī yào" 不死之藥 "drug of deathlessness" was another early name for the elixir of immortality. Chinese alchemists would "liàndān" 煉丹 (with "smelt; refine") "concoct pills of immortality" using a "dāndǐng" 丹鼎 (with "tripod cooking vessel; cauldron") "furnace for concocting pills of immortality". In addition, the ancient Chinese believed that other substances provided longevity and immortality, notably the "língzhī" 靈芝 ""Ganoderma" mushroom".

The transformation from chemistry-based "waidan" 外丹 "external elixir/alchemy" to physiology-based "neidan" 內丹 "internal elixir/alchemy" gave new analogous meanings to old terms. The human body metaphorically becomes a "ding" "cauldron" in which the adept forges the Three Treasures (essence, life-force, and spirit) within the "jindan" Golden Elixir within the "dāntián" 丹田 (with "field") "lower part of the abdomen".

In early China, alchemists and pharmacists were one in the same. Traditional Chinese Medicine also used less concentrated cinnabar and mercury preparations, and "dan" means "pill; medicine" in general, for example, "dānfāng" 丹方 semantically changed from "prescription for elixir of immortality" to "medical prescription". "Dan" was lexicalized into medical terms such as " dānjì" 丹劑 "pill preparation" and "dānyào" 丹藥 "pill medicine".

The Chinese names for immortality elixirs have parallels in other cultures and languages, for example, Indo-Iranian "soma" or "haoma", Sanskrit "amrita", and Greek "ambrosia".

The "Wenxian Tongkao", written by Chinese historian Ma Duanlin (1245-1322), and the "History of Song" describe how the Byzantine emperor Michael VII Parapinakēs Caesar ("Mie li sha ling kai sa" 滅力沙靈改撒) of "Fu lin" (拂菻, i.e. Byzantium) sent an embassy to China's Song dynasty, arriving in November 1081, during the reign of Emperor Shenzong of Song (r. 1067-1085). The "History of Song" described the tributary gifts given by the Byzantine embassy as well as the products made in Byzantium. It also described forms of punishment in Byzantine law, such as caning, as well as the capital punishment of being stuffed into a "feather bag" and thrown into the sea. This description seems to correspond with the Romano-Byzantine punishment of "poena cullei".