Farting into your own hand, then pretending to roll it into a ball and throw it at someone. Best if executed with an exaggerated wind-up.
The bitch is getting ready to unleash a stinkball!! Duck!
A ball of accumulated food/funk that varies in size, forms in the throat and then is dislodged sometimes involuntarily into your mouth when you are talking or clearing your throat.
The smell of it is comparable to Shit.
"I was talking and a stink ball came out of my mouth
When you are having sex with a chick who squirts, and she squirts before you pull out, whick makes the squirt go all over your balls, then drying up and making an odour called "Stink Balls"
Guy 1 "What's that weird smell"
Guy 2 "Sorry, my chick gave me stink balls an hour ago"