the art of poking a hole in a loaf of cornbread, slap butter on your wang, and then you stick your wang in the corndread, and have sexual relations with it. And after, you eat the loaf of cornbread.
The people who do this are usually called "Butter dicks"
"hey dude did you hear that Charlie Leland was cornbreading in his basement?"
"Yeah dudde, what a butter dick"