That's technically not possible
I'm an engineer this image has my mind spinning............I could probably build something, defiantly do you a solidworks model
It's not the mechanics of the act that melted my head, more the consent issue.
Split personality, maybe.
That might work, but is it rape if your other personality consents? And how are two personalities in control at the same time?
I'm thinking we need some kind of rape machine here. But then someone will have to activate it or start it up and if someone else does that wouldn't that mean that it's that person that's doing the raping? And if he starts it himself then he'd now that a rape was incoming. I guess it still would be rape as he still wouldn't consent and could fight back even if he started the machine himself though... Maybe the machine could initiate the rape at a random time so he'd not know when it was coming?