An ugly, fat woman. Usually a hook up as a last resort at a bar or night club.
Combines the words "heifer", and "loaf" as in meatloaf. Heifer refers to the size of the woman and loaf to what her skin presumably feels like.

to tell someone to calm down and relax.

when sitting on the can you really have to push hard to get that turd out. when you make that intial push you make a heph sound and at the end of the push you have your loaf. hense the name hephaloaf.