(Noun, Vulgar)
A deviant, typically of sub-continental origin, who derives particularsexual pleasure from the act of anally-violating females using his thumb (the opposed, short, thick finger with only two phalanges).
"Sen, the Thumbed Crusader, came home to de-grease his favouriteappendage following an active night of thumb-crusading." {Modern - 2OTH C.}