Go into the bathrooms and wait quietly in a cubical with a packet of mayo, when someone enters, start making fap-fap noises, make an climax sound and then squirt the mayo on the inside of the door and make it sound sloppy, then waltz out, pretending to zip up your fly and then if the person is standing there staring at you, freeze, act all embarrassed and shuffle sideways out of the bathroom, and when you get out, sprint towards the door, yelling "OH MY GOD SOMEONE JIZZED IN THE BATHROOM!!!!" and leave. I tried this once, I framed it on the dude who stared...