reverse masturbation

An act which is the inverse of masturbation; namely, when a person has sex with everyone else in the world but themself.

Bystander: “What’s he doing in that bathroom?”

Sexpert: “Could me more than masturbating…possibly reverse masturbation?”
Bystaner: “Noone is safe!”
Sexpert: “Reverse masturbation: it will be end of us all.”