Buns-up 

Ready for penetration from behind.

Frank Zappa: She was buns-up, kneeling...
Backing vocals: ................#buns-up...

(from "Dy-na-moe Hum")

Buns-up by Mathilda Underfoot February 6, 2010

buns up kneeling 

When a man or woman gets down on all fours and sticks his or her ass in the air, prior to being or during intercourse.

She was buns up kneeling, and I was wheeling and dealing.

buns up kneeling by Phantom Dick Lord July 2, 2018

candy up your buns 

It's when a guy has his Sweets all flushed down the drains

Hey, Mac, would ya candy up your buns?!?

candy up your buns by Jil Millrar December 2, 2013

Loosen up my buns 

A request for anal sex

Honey, will you loosen up my buns tonight?

Loosen up my buns by RSIM May 15, 2006

Blowing up my buns 

Farting

I had chili for dinner last night and I've been blowing up my buns all day!

Blowing up my buns by daysie78 November 3, 2009