# Where it is safe to strike > Which parts of the body can take impact and which cannot: safe zones, caution zones and areas never to strike, with the anatomy and the UK legal threshold. - Canonical URL: https://consensualspanking.co.uk/guide/where-it-is-safe-to-strike/ - Section: Safety and practice - Updated: November 2026 (2026-11-01) - Audience: consenting adults over 18 only. Everything on this site concerns consenting adults over 18. This is the page I most wanted when I started and could not find written down properly. The buttocks are safe because of what is underneath them. Everywhere else is a judgement, and a few places are simply not worth it. --- ## In short - The fleshy buttocks are the only area genuinely suited to repeated impact. Thighs are workable with care, within two constraints: the sciatic nerve and visible marking. - Kidneys, tailbone, spine, backs of knees: never. Genitals, perineum and anal area: never, and it is the clearest one on the list. - Hands carry real fracture and tendon risk. Light and symbolic only. - Under *R v Brown* (1993), consent is not a defence to actual bodily harm in England and Wales. Everything below comes down to one question: what is directly underneath the skin you are about to hit? Fat and large muscle absorb impact. Bone close to the surface transmits it. Organs and nerve bundles do not tolerate it at all. - **Safe.** Fleshy lower and mid buttocks. Effectively the only area built for this. - **Caution.** Upper and outer thigh. Sciatic nerve runs down the back of the thigh; marks show far more and are harder to cover. - **Never.** Kidneys and lower back, tailbone and spine, backs of the knees, and a hand that comes back to cover. Light strokes to an open, offered palm are a separate practice, covered in [hands and the tawse](https://consensualspanking.co.uk/guide/hands-and-the-tawse/). ## The safe area The lower and middle buttocks, over the bulk of the gluteus maximus. There is a decent layer of subcutaneous fat over a large muscle, no organs behind it, and the nearest bone is deep enough that you have to be careless to reach it. Even here, aim matters. Work the fleshy part in the middle and low. Drifting upward takes you towards the tailbone and the kidneys. Drifting outward takes you to the hip, where the bone is much closer than people expect and where a hard cane stroke will hurt in a way that is not enjoyable and can bruise the periosteum. ## Thighs: yes, with two real constraints The upper and outer thigh takes moderate impact fine. Two things to hold in mind. The sciatic nerve runs down the back of the thigh. Heavy repeated impact along that line can cause nerve pain and numbness that outlasts the session by a considerable margin. Keep heavy work off the centre-back of the thigh. The second constraint is social rather than medical. Thighs mark more readily than buttocks, the marks sit lower down the leg, and they are visible in anything shorter than trousers. Plenty of people who were entirely happy on the night have discovered this in a changing room the following week. It is worth raising during negotiation rather than afterwards. Inner thighs are a different proposition again. Thin skin, major blood vessels, lymph nodes, and a great deal of sensitivity. Light only, and not at all until both of you have a lot of practice. ## Areas that are never worth it ### The kidneys and lower back The kidneys sit higher and more exposed than most people assume, roughly level with the bottom of the ribcage towards the back. Blunt trauma there causes genuine injury, and the symptoms can take hours to show. There is no version of this that is worth the risk. ### The tailbone and spine The coccyx is small, superficial and fractures easily. A coccyx injury takes months, makes sitting miserable, and has an unpleasant habit of becoming chronic. ### The backs of the knees Nerves and vessels close to the surface, very little padding. ### Head, neck and joints Obvious, but people get carried away and implements bounce. ### The genitals, the perineum and the anal area This one gets asked about often enough that leaving it off the page would be dishonest, so here it is plainly: it does not belong in this activity at all, and it is the clearest never on the list. The reason the backside works is a thick layer of gluteal muscle and fat sitting over bone, which spreads the force of a stroke across a wide area. None of that exists between the legs. The skin is thin, the nerve supply is dense and close to the surface, and the tissue is far more vascular than skin elsewhere, which is why injuries there bleed and swell out of all proportion to the force involved. The pain is also not the pain people are expecting, and it does not behave like the pain of a spanking. What actually happens when people ignore this is specific. Haematomas that spread and take weeks to resolve. Tearing of tissue that was never designed to take blunt impact. Blows to the testicles carry a risk of rupture, which is a surgical emergency, and a hard enough strike can cause it. The anal margin splits readily, a fissure there is disproportionately painful and slow to heal, and the sphincter is a piece of equipment you need to work properly for the rest of your life. Broken skin in that area is also broken skin in the most bacterially contaminated part of the body, sitting next to mucous membrane, which raises both ordinary infection risk and the transmission risk of anything either person is carrying. There is a further problem that makes all of the above worse. These are exactly the injuries people will not take to a doctor, because they cannot face the conversation, and a treatable thing left for a fortnight out of embarrassment is how it becomes a lasting one. This is not only a warning about aiming there deliberately. A cane tip is the fastest-moving part of the implement and it wraps, and strokes aimed too low, across the crease rather than on the fleshy part above it, catch the perineum without anybody intending it. That is a large part of why the target area on this page is drawn where it is, why a stable position matters, and why [unstable positions](https://consensualspanking.co.uk/positions/standing-against-a-wall/) and long implements are a poor combination. Legally it is the same picture as the rest of the page, only sharper. Injury of this kind reaches the actual bodily harm threshold easily, and after *R v Brown* consent is not a defence to that in England and Wales. The person holding the implement carries it. If the appeal for you is about that area being private rather than about impact landing on it, and in my experience it usually is, then the thing you are after is exposure rather than force, and all of it is available without any of this risk. Being undressed, being looked at, being made to hold a position, being inspected against a standard. That is covered at [being bared, exposed and inspected](https://consensualspanking.co.uk/guide/being-bared/), [arching and presenting](https://consensualspanking.co.uk/positions/presenting/) and [inspection](https://consensualspanking.co.uk/scenes/inspection/). > **If an injury happens there.** Get it looked at the same day rather than waiting to see how it goes. Bleeding that does not stop, difficulty passing urine, a testicle that is swollen or severely painful, a wound that gapes, or any spreading redness, heat and fever needs urgent assessment. Bleeding that will not stop, a swollen or severely painful testicle, and fever all mean A&E rather than a GP appointment next week. > > > > NHS 111 will tell you which, free, at any hour. Nobody at a hospital needs to know how it happened, and they have heard considerably stranger. Embarrassment is the thing that turns a manageable injury here into a permanent one. ## Hands and the tawse This deserves its own treatment because the interest in it is genuine, and I do not want to pretend otherwise. Plenty of adults want a strap across the palms, and that is an entirely legitimate thing to want. The anatomy is nonetheless what it is. Each hand has 27 bones, with tendons and the ulnar and median nerves running close to the surface and almost no protective padding. Hit that structure hard and it swells, splits and bruises as a matter of routine. I want to be fair about the risk rather than alarmist. Consensual adult play at moderate force is a long way from full-force strokes with a heavy leather tawse. Fractures are uncommon, and bruising and swelling are the usual outcome when it goes too far. But the margin for error is much smaller than on the backside, the injuries are more consequential when they happen, and there is no fatty tissue to give you any room. If it is part of what you want, keep it light and largely symbolic, use a strap rather than a cane, stop at the first sign of numbness or tingling, and accept that this is one of the few areas where the fantasy and the safe version differ considerably. See [hands and the tawse](https://consensualspanking.co.uk/guide/hands-and-the-tawse/) for the practical detail. > **The legal line.** In England and Wales, *R v Brown* (1993) established that consent is not a defence to causing actual bodily harm during sadomasochistic activity. Transient redness and light bruising generally sit below that threshold, and heavy bruising may not. A fracture does not. This is a real reason to avoid the hands specifically: it is the injury most likely to cross a line that consent cannot uncross, and both people are exposed if it does. More on [UK law](https://consensualspanking.co.uk/uk/is-it-legal/). ## Implements change the calculation A hand is forgiving. It spreads force over a wide area and it hurts you too, which is an excellent built-in governor. Canes concentrate force into a narrow line and can break skin without much warning. Straps and paddles spread it but carry more weight. Anything with an edge, a seam, or a rigid tip will find bone. And every implement has a different wrap-around behaviour: the tip travels furthest and fastest, which is how people accidentally hit a hip when they were aiming at the middle. The rule I use is to spend the first dozen strokes with any new implement finding out where it lands rather than how hard it can go. ## Read next - [Cane types and grades](https://consensualspanking.co.uk/implements/cane-types/) - [Hands and the tawse](https://consensualspanking.co.uk/guide/hands-and-the-tawse/) - [Marks and bruising: how long, and hiding them](https://consensualspanking.co.uk/guide/marks-and-bruising/) - [Implements and what each one does](https://consensualspanking.co.uk/guide/implements/) - [Is any of this legal in the UK?](https://consensualspanking.co.uk/uk/is-it-legal/) ## Sources 1. *R v Brown* [1993] UKHL 19, House of Lords. [bailii.org](https://www.bailii.org/uk/cases/UKHL/1993/19.html) 2. NHS guidance on kidney injury and coccyx injury, [nhs.uk](https://www.nhs.uk). > **Not legal advice.** Where this page mentions the law, it is general information written from an England and Wales position unless it says otherwise, and it is not legal advice. Scotland and Northern Ireland have their own law. If your own legal position matters, speak to a solicitor. ## Common questions ### Where is it safe to spank an adult? The fleshy lower and mid buttocks, over the gluteal muscle. That area has enough fat and muscle to absorb impact without underlying organs or bone close to the surface. It is effectively the only region suited to repeated impact. ### Is it safe to spank the thighs? The upper and outer thigh can take moderate impact. The sciatic nerve runs down the back of the thigh, so heavy strokes there risk nerve pain or numbness. Inner thighs have thin skin and major blood vessels and should be light only. Thigh marks are also more visible and harder to conceal than buttock marks. ### Is caning or strapping the hands safe? The hands are a high-risk target. Each hand has 27 bones with tendons and nerves close to the surface and very little padding. Injuries there heal slowly and can affect function. Light symbolic strokes are one thing. Full-force strokes leave hands split and swollen. ### What areas should never be struck? The lower back over the kidneys, the tailbone and spine, the backs of the knees, the neck and head. Blunt trauma over the kidneys is genuinely dangerous, and coccyx injuries are slow to resolve and can become chronic.