Placing one's fist into another's rectum (also known as fisting) and then proceeding to fanning open the hand and fingers, creating a blooming onion-like appearance.
by Taylor, B October 29, 2005
A woman's genitalia that hasn't been properly cleansed over the course of a week to month. In order to be a blooming onion, this vagina has to have an odor that burns a man, or woman's, eyes as they approach for oral intercourse. When spreading the vaginal lips apart, one must cry from the odor, else the genitalia isn't a proper blooming onion.
Evan was so drunk last night, he licked a prostitute's blooming onion. He woke up this morning with a hangover, a bad taste in his mouth, and crazy red eyes from crying all night long!
by Mr. Booze May 13, 2010
"Man, when she took of her dress and asked me to fuck her in the bum, my eyes popped out when I saw that blooming onion staring at me."
by Jtron 3000 September 08, 2003