When your girl sticks a raw Koegel sausage in your butthole and wiggles it around until you orgasm. The acidity will make your ass feel like it's on fire but it's worth it if you can handle it because your ass will go numb and you will nut harder. The name derives from Flint, Michigan where there is a Koegel Sausage billboard right on I-75 near where all the roads are stacked on top of each other. If you've driven through Flint, you know what I'm talking about.
Ron: "My girl and I were getting kinky and she gave me the flint sausage fondler. DAMN I haven't felt that good in a long time."