As of now probably choking myself, and if I set it up right trigger hypotension.
For choking, I hit the carotid artery just until I pass out, and then let go. My whole body goes fuzzy, hearing is smothered, and I stop thinking at all for about twenty seconds.
For hypotension, I avoid eating and drinking water and proceed to drink pomegranate juice and pure hibiscus tea and let myself loose, mostly just a minor headache, shallow breathing, and feeling dizzy and difficult to think clearly. It's not as strong as choking, and it only works if my current BP is very low already, but when it's done right I feel lost in my head for a few hours. To be honest, I don't know if it's actually a hypotension thing or a placebo, because I don't see people discuss it and it just seems to be a "me" thing. Regardless, I feel something and it feels nice. I wish I could get my hands on hypotension medication but none are OTC.
I've been cut free for five years and it left scars. The two I do now don't. I've been mentally restraining myself for rapidly punching myself in the face and glad to say I've stopped that.
I don't recommend SH at all. It is addictive, I wish I can stop. I don't want my answer or this thread to be inspirational to those who are curious. I'm not having fun, I'm inappropriately coping.