A tatoo, sometimes facile, while other times embellished and elaborate that is typically found on the lower back of females sorority girls, raver chicks, strawberries, fresas, girls gone wild, spring break enthusiasts, wanna-be's, mattress-backs, etc., above and around the butt crack and at times extending therein...
Sometimes used to cover or take notice off of significant stetch marks or cellulite...
Look at that (enter female descriptive word of choice) crack-tat; Fuck man! check out that bitch's hot ass crack-tat; Christ! that is the weakest excuse for a crack-tat I've ever seen; In chemistry class, Alice bent over to pick up her dropped book and I saw her fucking knarly ass crack-tat.
The imprint that is left on the back of a toilet seat by someone (usually a fat ass) who has not been diligent in wiping. The combination of sweaty ass-crack and residual shit results in the depositing of a brown streak on the toilet seat. Most commonly found in public restrooms.
Man, I really had to take a dump this morning, but someone had left a crack-track in the first stall. So I moved on down the line.