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2.
1) a sex act done under a morbidly obese woman, similar to the Western Whormelt, but this will be done with her legs propped behind her head 2) full definition, the male enters the womans anus from behind, spins himself upside down and wedges himself under her gearth, as he fights for air the erotic asphyxiation causes a heighten state of panicked arousal, and an explosive ejaculant can be achieved

any number of partners may be added the limit is only in ones imagination, but remember if additional partners are added the name is changed to properly represent the situation, Double Cleavin, Triple Cleavin, Octocleave even the elusive AutoCleave "i've seen it done" example below

first mentioned in an episode of "family guy" as a dirty word

also can be spelled Kleavin, from the root word cleave : to adhere firmly and closely or loyally and unwaveringly
Becky gave up the the cleavin last night, you can see Jim's jizz on the fan blades, he vomited all over the duvet

Roberta the superfat hermaphrodite almost died AutoCleavin with her cock up her butt and her boob in her mouth, that biker dude just happened to hear the commotion and broke into the window to save her, or was it to ass rape her before he left town, not sure but both happened
by Cosmic Pope October 29, 2010
 
1.
Contraction of "cleavage leavins": the food that falls into one's cleavage while eating, and found later to be eaten as a snack.
"I always have so many cleavins after eating popcorn at the movies."
by Femme Brulée January 16, 2012