look up any word, like plopping:
Pin Tummy is when you are about to start a wrestling match and you look at the guy your about to wrestle and notice he has a gut. You then instantly know you are going to Pin him.
This guy is going so down he has some serious pin tummy

hey bro you see that kids pin tummy, yeah dawg he's huge.
by thatlaxguy28 December 13, 2010