The presence of perspiration soaking through one's shirt located under a fat man's breasts, much like that which occurs in the arm pit.
In a hot college basketball stadium:
Student 1: Whoa look at that guy's pit stains.
Student 2: Dude those aren't pit stains, they're tit stains.
Student 1: Whoa look at that guy's pit stains.
Student 2: Dude those aren't pit stains, they're tit stains.
by D.Swan December 21, 2008
Get the Tit Stainsmug. the moist line a fat girl gets between her gut and tits when she sweats. this usually occurs on a hot day. extremely noticable when a bigger girl wears a smaller shirt.
by heatmat August 30, 2006
Get the tit stainmug.