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A sex act believed to have originated somewhere in the Orient around World War II. Said act consists of one partner performing anilingus (commonly referred to as a “rimjob”) on another until the recipient gives way to spasmodic evacuation of the bowels onto the partner’s mouth. Said partner continues applying anilingus until the bowels are fully emptied into and around the mouth, at which time the sex act is complete.

“Our sex life wasn’t that great until my husband started “eating a grounder” last night. Now it’s fantastic."
by Ted Cawkwell March 28, 2007
While giving a rimjob, a girl sharts (shits and farts) while you mouth is open, but you keep going
I went down on my girl, but she had taco bell earlier and I ended up eating a grounder.
by ST,PE,MB March 22, 2007