Butt-ups 

A type of shorter-all with straps tight enough to raise the posterior accompanied by a deep v-cut on the front and/or back side

Given his low budget, Brian was forced to wear his denim butt-ups & a tie (no shirt otherwise) to his sister's wedding.

Butt-ups by Websterman October 10, 2016

upsidedown butt chug 

After butt chugging a beer, your remove the funnel, put it in a friends mouth and they chug the beer out of your ass.

"Yo man, can you believe Blake just upsidedown butt chugged that from Averys ass" upsidedown butt chug

upsidedown butt chug by TomPizzle February 10, 2017