Jesus Christ Almighty. It's just fucking sex. Sometimes, a man has needs. And it just so happens that at that same time, a woman has the same needs. And fate would have it that this man and woman happen to be very good friends, so they already have this established connection between them which makes it easier for them to get close to each other without awkwardness. They also see each other quite a few times. There's an undeniable physical attraction between the two. None of them currently have any other ties, but both of them have so many things on their mind already that they don't want any additional burden and complications on their shoulders, whether it's because of extremely difficult classes or simply because of stress. Finally, they find themselves in the same room, alone.
Why the hell would anyone deny themselves a simple act that will bring them satisfaction and pleasure?
Sometimes, it just fits. 2 days ago, it happened to me. It fit. After all the inital confusion/awkwardness/mental chaos, we set the ground rules (she even was the one to say the term "friends with benefits"), and although there is some confusion in what may happen in the future, sometimes, you just have to go for it, partly because it's a basic need that you satisfy and it will make your day brighter, and partly because there is no damn reason not to. You can't help it, because you'd feel stupid if you did. I know I would have. And right now, I prefer it so much better this way. It's amazing.
By the way, fuck friend != friend with benefits.
Fuck friend is a booty call, in that you're friends with that person for the sole purpose of sex. Maybe that's what Olimario is against. A friend with benefits is a friend first, that you sincerely care about, but who happens to be a bombshell, and a day came along where the two of you fit perfectly well together. I have absolutely nothing against people with fuck friends. But when it comes to a friend with benefits, you'd be a damn idiot going ahead with it if you're unwilling to have a REAL, "official" relationship between the two of you, if it ever was to happen. Don't go into it if the possibility of a successful relationship between the 2 of you is not there.
That means that even though we both want to avoid all of the mindfucks that come with a relationship, at least for the time being, we know that we would still be willing to give a relationship a try someday in the future, if it ever came to that point between us. Sure, this is all very complicated at first, but if the two people involved are rational, stable, and smart enough, it gets extremely clear. We both have enough self-control and respect for each other so that if one of us starts developing non-mutual feelings for the other, we won't throw a damn, pointless tantrum, and we'll do everything in our power to prevent it from blowing up in our face, even if that means that we're gonna have to talk about it. In the event that she finds another guy to have a relationship with and (let's assume) I have a problem with that because of unwanted feelings that would arise : if she's happy, I would be a fool to impose any pressure on her and become a burden, and I'd regret that much more than simply not being with her. That's how you make these things work. Stay rational.