The bulge formed in a man's genital area, caused by sitting down with jeans. The zipper bunches up, forming an erection like bulge, which can scare and excite all who are there to witness it.
"FUCK, IT'S JUST CAREERS CLASS DON'T GET ALL EXCITED ON ME"
"Calm down man, it's just a zipperection."
"Oh. Haha, it's pretty funny."