I've jerked two friends of mine in my teens, but we didn't get to rub. Too bad :)
I really like these kind of scenes or pics, although you don't see it often.
Having fun with a jerk off buddy, including mutual handjob, cock to cock rubbing, is one of my turn ons. I think that should be normal for two or more friends to say like : 'I'm bored with the Playstation, how about jerking off and rubbing dicks?' without any kind of afterthought. Just another way of having fun :)