Actually I think it's kind of interesting... Sexual encounters leave a trail of emotional and spiritual bonds, besides the physical union. It's interesting the repationship you may have with the other guy because you must share aomething else in common to find yourself with the same girl. What is it about her that got you both? What did she see in both of them? Once you fuck someone you are tied to them for life, like family...To have gotten intimate like that, they are in your closed circle, and so people you slept with are brothers in this circle, too as they were once one with or part of you. I've seen some two guys one girl triangles where they seem to really have a brotherly love for eachother and a joint sense of duty of care towards the girl. When it's two girls one guy everyone just gets their eyes scratched out. I think when you sleep with someone you have to consider they are the sum of all their previous partners in a way and where they have been and the types of people they allow to get so close are further contributions. I'm the kind of person who would want to know all about an ex. What was she like right down to gory details... Because she was once part of you so it is important to me.
As for physical practicalities all the sluts make sure you douche the other guy's spunk out first and guys wipe your dick before going on to the next one. Lol