Researchers also use working categories rather than one fixed taxonomy. A 2019 systematic review of BDSM research found no consensus on which activities count as BDSM, and reported that studies asking about the umbrella label produce different results from studies naming specific activities. The boundary depends partly on what the researcher is measuring.

A study of 1,580 women recruited from kink communities grouped 126 behaviours into BDSM-related behaviour, roleplay, exhibitionism, erotica, fetishistic behaviour, overt sexual activity, and a miscellaneous group. The paper explicitly said its categories were not rigid. The same interest can sit in more than one workable category; there is no single official map.

Ask several questions of the same interest: What role is involved? What feeling or stimulus matters? What story frames it? Is there a focused object, material, or body feature? Does a relationship structure or setting carry the appeal? More than one answer can be central.

Role interests answer a question about position: who leads, follows, gives, receives, serves, directs, performs, watches, or takes on a character. Dominant, submissive, switch, top, bottom, caregiver, little, owner, pet, handler, and service roles sit here, although not every role involves authority.

Power exchange is more specific than taking a practical role. The National Coalition for Sexual Freedom's terminology glossary defines top and bottom as the doer and receiver in an activity, while D/s describes a hierarchy. It says the dominant is commonly the top and the submissive the bottom. A top may perform bondage while the bottom directs every choice. A submissive may give authority without receiving any physical activity.

Roleplay adds a fictional frame. Uniforms, medical scenes, pet play, adult age play, and character scenarios may use power, but the character itself can be the main attraction.

• Authority: dominance, submission, switching, protocol, service
• Activity position: top, bottom, versatile roles
• Persona: pet, handler, caregiver, adult little, medical or uniform character
• Social position: praise, humiliation, objectification, ownership symbolism

Sensation kinks centre on what the body feels. Impact, pressure, texture, temperature, tickling, scratching, biting, electrical sensation, and sensory restriction all belong in this branch. Some interests seek intensity; others seek delicacy, contrast, rhythm, surprise, or the calm produced by a narrow field of attention.

Restraint often sits between sensation and power. The physical feeling of rope or cuffs can matter on its own, while restricted movement can also support surrender, visual composition, predicament, or discipline. Impact can likewise be about pain, sound, marks, performance, punishment, or playful reaction.

The practical demands differ sharply across this category. A label that says 'sensation play' is too broad to guide technique. Once you know the specific activity, look up its physical effects, equipment, and release needs.

Fantasy categories group interests by story. Being discovered, watched, transformed, pursued, controlled, corrupted, shared by a partner, or placed in an impossible situation can be exciting because of suspense, symbolism, emotion, or the suspension of ordinary rules.

A fantasy label does not say whether someone wants a literal real-world version. Many scenarios are appealing precisely because imagination controls the camera, pacing, consequences, and ending. In fantasy and roleplay, coercion, sleep, mind-control, and discovery themes can be explored without involving an unwilling or unaware person.

A transformation fantasy can contain body focus, clothing, or power and still be mainly about an impossible story. When the interest is a real practice, its physical details matter more than the fantasy label.

Fetish categories organise attraction around a distinct focus. That may be a body part, scent, material, garment, object, texture, or visual feature. Feet, shoes, boots, leather, latex, lingerie, masks, hoods, muscles, and size contrast commonly appear here.

The focus can combine with activity and role. Boots may be attractive for their material and shape, as a symbol of authority, or as part of worship and service. Scent may be bodily, material, intimate, or connected to a particular person. The fetish label identifies the centre of gravity, not every layer of the fantasy.

Kink and fetish overlap, but the words are not always interchangeable. Fetish usually puts a particular focus at the centre, while kink can describe the wider activity, role, or fantasy around it.

Some interests are best organised by the relationship around them. Ongoing authority, service, protocol, collar meanings, partner-sharing fantasies, and forms of erotic performance depend on who the people are to each other and what persists beyond one activity.

Context can also be the main feature. Public-performance fantasy differs from private exhibition for a camera. Group structure differs from watching. Formal protocol differs from a dominant style. These distinctions matter because a broad category can blur the part that creates the appeal.

Start with the feature you would miss most if it disappeared. If removing the command ruins the fantasy, look under power. If removing the material ruins it, look under fetishes. If the story still works only with a particular relationship, start there.

You do not need to force an interest into one box. Choose the nearest category, then check the most specific term. A focused quiz can compare patterns within one subject; the broad Kink Test can help you notice themes across several without issuing a final identity.

When two labels seem equally accurate, describe both layers. 'A leather fetish tied to dominance' and 'a restraint kink focused on helplessness' communicate more than a single tag. Category overlap is information, not a classification error.