I'm curious... How many of you men can simply not cum by vaginal penetration? I've met a couple of men who can just keep going and going but cannot cum that way. they have to jerk to cum (preferably while being rimmed or having their balls stimulated). I'm wondering how common this is. One man told me he worked hard at not cumming too fast when he was young and now he just can't cum that way. Does this make sense?