This is a term for getting a blow job from an elderly women who has taken her dentures out. She will "gum" the penis into a sensationally different and some would say a better feeling experience.
"Hey grandma, tell your roommate to come here and give me a sloppy jalloppy"
"Hey, how much for a good sloppy jalloppy?"
"Hey, how much for a good sloppy jalloppy?"
by Moonbouncer September 28, 2008