The foamy build up beneath the foreskin of a nasty penis, usually during intercourse or masturbation. Really gross if left to ferment too long.
She thought twice about giving him head when she saw and caught a whiff of his neck butter.
The undigested corn in shit. Has also been found stuck to the tip
after withdrawing during anal (uncommon, but true).
Dude, I was doing her in the poop chute and pulled out a stink niblet.
Well, you are now known as the 'Kernel'