The hard on rubbing against your face would bother you ?
Look, there is very little sexually that bothers me.
Poo during anal sex? check.
Puking during a deep throat? check and yes please, do it again.
Being snowballed after a good blowjob? check.
Taking a strap-on? Check.
etc
In college many many many moons ago, I did a MFM with my roommate and his GF while we were rolling on ex and high as a kite. Him in her pussy, me in her ass. For whatever reason, I pulled him out, blew him for a bit and then went back to doing my thing in her ass. It was just one of those drug fueled "in the moment" things I did in my college years. Yes, the next day it was fucking awkward for so many reasons but that was near or at the top of the list. But it's whatever. We moved on and that was that. But if you're worried about crossing swords during a DP and somehow that makes you "gay", you have issues. Seriously. If you're worried that you'll think about the other guy instead, hate to break it to you, you might be bi-sexual. But if you're enjoying some chick and balls touch, just saw "whoops" and move on. It's not that big of a fucking deal.
It's kinda like the whole strap-on thing. "Oh I wouldn't do that, only
fags put things in their ass" when in fact role reversal with a woman is not only fucking hot, it usually leads to even better fucking after the fact. I've always said a guy needs to have something equivalent to his dick put up his ass before he tries to fuck his lady friend in the ass. Makes him appreciate the effort a tad bit more.
But anyways, yes, I would be a bit upset if the dude tried to slip his cock in my face or up my bum but if we're talking about a guy watching me fuck his wife or we're doing a DP on her or he's a cuck and wants to clean up the mess I leave behind, it's whatever. It really doesn't bother me at all.