A reverse burp. A sound caused by the release of gas from the digestive tract, within the oesophagus. Unlike a burp, however the mouth remains closed and the action itself is involuntary. The word is derived from "burp" spelled in reverse.
white guy number 1: AughHG
white guy number 2: Dude what was that?
white guy number 1: Bro it was like a burp, but backwards
white guy number 2: Bro u just did a prub!
white guy number 1: holy shit dude i did
The "pregnancy nubbin." It is formed when a woman is at least 6 months pregnant and her belly button, even if it was previously an innie, protrudes outward like a gigantic nipple in freezing weather.
Guy 1: So Scott's wife is pretty far along, I see.