An act of anal sex where the female (or male) has not used an enema before intercourse and purposely tries to defecate at the same moment of penetration, thus resulting in fecal lubrication of the rectal cavity. Continued sexual intercourse causes the excrement to eventually engulf the entire penis and testicals of the man. A position usually done in "scat" movies.
Jim paid Jane $400 extra to give him "shitstained balls."
When a bitch ass mother fucker fucks his stupid bitch so fucking hard in the pussy from behind so that his hairy fucking atrocity of a ball sack slams violently into her filthy, hairy asshole resulting in large amounts of her shit spraying in all directions, covering the fucking bitch shit cock ass mother fucking cocksucker's nut sack in a thick layer of shit, most likely due to the fact that the stupid slut probably forgot to wipe her fucking bitch ass cunt whore pussy licking fucktard asshole last time she took an almighty shit.
"Last night i ambushed my girlfriend in the bathroom while she was taking a hearty shit and proceeded to fuck her from behind, and i ended up with shit-stained balls.