Btw, for any transitioning transharmfuls who are systems*, your own other alters* are suuuper easy victims btw. And I'm not talking just about headspace* stuff.
One really fun thing some of our people like to do is to take control over the bodys limbs, while allowing someone else to be in control of the brain and thinking and stuff, and then the perpetrators like to forcefully/violently fuck the body (usually with a weapon or otherwise unsafe object in our case) without telling or warning whoever is in head control. They often times also like to lock front or otherwise somehow keep the other person there the whole time and fully concious. This typically gives the other alter the emotional and sometimes physical reactions/response that "regular" r/pe would! :)
Of course, this specific method requires having a certain level of control over your system* and other alters*, but if you can manage it— it's a really easy, free, and convenient way to (help) transition