(1) verb. The act of sucking or licking ejaculate (or other substances mixed with ejaculate) out of the orifice in which they were deposited. Most commonly used to refer to sucking out semen after anal sex, but technically sucking the semen out of your girlfriend's pussy is also felching
(2) Noun, referring to the substance ingested during the act of felching--generally a mixture of semen and other bodliy fluids (feces, sweat, vaginal fluid, etc.)
I couldn't belive it. After Nigel packed my ass, he felched me!