Chapter 0 - A little tale

Thursday, April the 28th, a few minutes before 5:30 P.M.
College's males bathroom at 2nd floor.

I was in a stall, you know, pooping, checking stuff in my phone... the regular thing. I was about to leave, when suddenly, I heard voices of a couple, a guy and a girl, approaching. First, I didn't pay attention, after all, it's a college. One hears any kind of conversationts from any people there. As the voices felt more and more inside the bathroom, I realized "wait, this is a men bathroom. 
What's a girl doing here?... Oh no... don't tell me they both are about to do something dirty-!". Right in that moment, I heard that they both got in together in the stall RIGHT NEXT ME. I was "ooooohhhhh nooooo theeey wiiiiiiill..."

But then I put attention in what they said (I don't remember it exactly, it's quite vague)

As they both approached to the stall...
GIRL: are you sure? What about if there is somebody?
GUY: C'mon, there won't be anybody.
(That's right. By that time, there are almost no subjects on 2nd floor's classrooms, so no need to be there)
While they got in the stall...
GUY: Okay, there you go.
GIRL: Ugh, don't you hate when you have to resist the urge?
(For the way she said that, I assumed she meant having sex)
(Then, I heard a pee. A long and lousy pee)
(Ooohh... she meant holding the pee... probably the women bathroom was closed or something. Right, what other reason to go to men bath? [SEX, YOU IDIOT!] oh yeah)

Then, I heard some noises that I couldn't tell, but in that little instant, a twister of ideas got in my head.
"what about if they have sex? Should I masturbate and cum while I get excited by their noises? Should I join them? Should I fap and cum and then join them? It's not a bad idea to join, nobody around, the place is quiet, a cramped threesome, we could make it more passionate... [yeah, or maybe they'll get scared, they cease and leave, leaving you like a fool. No, don't interrupt them!] But sex in college! What a better place to do it-?"
In that instant, I hear the lock of their stall getting unlocked. And just like that, they left. They said something, I don't remember, they talked in an undertone. The best I could think of to do after seeing there were no sex, was coughing. Quite a loud one, just so they find out there WERE somebody, but apparently, they didn't hear it.
And that was all. Very frustrating, but man, how intense and exciting. That day, I left the college and went to bed with some many hot thoughts.