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3.
When a woman farts whilst having anal sex.
Oh shit, bitch! Did you just billow? Now my one eyed viper's got pink eye.
by Matt McDouche December 17, 2008
 
1.
The quality of having or being billowy, cloud-like, fluffy, or otherwise over-flowing. Often used to refer to ladies with big, squishy natural breasts that you wanna sink your face into
Im always on the search for billows that way i can rest my head without bringing around a bunch of pillows
by trixxy b damned November 10, 2006
 
2.
Play on the words "butt" and "pillow".
"Aw man this seat is uncomfortable. Can i have a billow?
by ILikePieSalad September 21, 2013