Describing area below a chicks belly button and abover her vag. In this case it's that small/large bump that's more noticable when a chick wears jeans.
Refers to a time when I brought a chick home and watched her undress. She was not a thin girl but not fat. She wearing a pair of really tight jeans that looked okay on her but when she unbuttoned the last button her whole belly fell out. I just about threw up. It reminded me of carring a full bag of trash and at the last second the bag explodes and all the garbage spills out onto the street.
Example: Look at the Bbog on that chick!