Ballsac Gravy Share definition Flag When you wear underwear that isn't breathable and your junk gets really sweaty, it creates a problem in your pants known as Ballsac Gravy. I'm really glad I wear Pair of Thieves underwear, it eliminates Ballsac Gravy! Ballsac Gravy by Uploads of Fun March 25, 2020 Get the Ballsac Gravy mug.