Little back story:
So I've been dating this girl for almost two years now. We click great, have a ton of things in common, and are pretty much best friends.
I ended up in this relationship about half a year after getting out of another LTR. As such, I feel like I've been missing out on the spontaneity of hook-up culture. Anybody I've ever asked says I'm not missing out on anything, and that what I've got with this girl most people never find, yada yada yada.
I can see this going the long run, for sure. But I can't help but wonder if the grass is greener on the other side of the hill.

So the other day I was on a yik yak like app (basically just a completely anonymous feed where people can post almost whatever they want) and commented on a post from a girl who made a comment about hooking up with a rando on campus for a quickie.

I jokingly went along with it, not expecting it to ever go anywhere (cause who hooks up with a stranger on an anonymous app, right?). We exchanged snapchats to plan where to meet up and see what each other looks like, and this chick is pretty smokin'.
Not only that, but she's actually down to meet up for a rando quickie.

So here's my dilemma. My heart and my morals say no, but my curiosity and my member say yes.
Chances are, I'll get away with it.
I wouldn't want to ever hurt the girl I'm with though and never considered myself the type of person to do something like this, but it sounds exciting af.

Advice?