Guys, sexual cannibalism isn't actually part of the mantis mating ritual and is only rarely observed in nature when food is scarce. The idea that the female mantis eats the head of their mating partner is purely pseudo-intellectual pop-science meant to push headlines and has been debunked for almost forty years now. As long as you make sure your mantis waifu is happy and properly fed, you may copulate with her as much as you want.