A rusty towball is when you are smashing a chick in the ass and then when you pull your cock out of there you have a big lump of shit on your helmet.
my mate Ryan was fucking this chick the other night and half way through fucking her up the ass he pulled his cock out and to his horror he found his helmet covered in shit. she gave him a rusty towball.
by bjeloga the wogga February 3, 2013