When having sex with a woman/girl and her poon dries up because she has had too much to drink but is still coherant causing you to have to reach for substitute forms of lubrication.
Dude!! Me and Sallysplit a bottle of Jack Daniels and romped so long she got Whisky Twat and I had to use my spit to finish her off....
The mark and/or odor that is left on an object after a nude menstruating woman has seated herself upon it.
Regular twat stamps are inherently all but invisible, but they may be easily detected by a person or animal with a keen sense of smell.
By contrast, crimson twat stamps are more distinctive, by both sight and odor.
see also: murder scene
Donnie's mattress looks like the aftermath of a Sex Pistols concert due to the excessive number of crimson twat stamps on it. One thing's for sure, he is not afraid of Aunt Flo.