The act of folding the excess body cleavage of an obese man or woman, typically used for making sweet love to an alternative orafice. Crisco, rendered bacon fat and luke warm butter are all optional.
Leroy: Dude, I went hoggin' on some white bread last night.
Darryl: Did you get the stank?
Leroy: (ashamed look)
Darryl: Don't tell me you went flapjackin' again mothafucka!
Leroy: It wasn't my fault, dat bitch passed out cold so I found a flap and I jacked it!
Darryl: Hell yeah! Jack dat flap negro!