Informal, Often, Used with the verb play Sexual groping; erotic horseplay.
[T]hey wouldn't do any work then, just hang around and drink and play grabass with her and she didn't want that.1976, Thomas Glynn, Temporary Sanity: A Novel, →ISBN, page 66:
Bobby was bear-hugging Sammy Vaughn and then playing grab-ass with Sammy's ex-wife Alice.1997, Lee K. Abbott, “Chapter One of Wet Places at Noon”, in New York Times, retrieved 11 Dec 2015:
1 more example
"I'm thinking a rousing game of grabass is in my future while you load the dishwasher." . . . "So y'all plannin' on grabbing my ass?" "That and a few other tempting body parts."2010, Regan Taylor, The Glass Cage, →ISBN, page 81:
2
Informal, Often, Used with the verb play Rowdy behavior; general horseplay or foolery.
There's no playing grab-ass or fighting in the building. You got a grudge against another man, you fight him Saturday afternoon. Any man playing grab-ass or fighting in the building spends a night in the box.1967, Cool Hand Luke, spoken by Carr (Clifton James):
"Anything else? Yes, Lieutenant Lemmon?" "Yes, sir," Lemmon drawled. "How do I get out of this chicken-shit outfit?" "Knock off the grabass, Glen. Okay, listen up. When you brief your people, make it clear that our mission is defensive only."1977, Philip Caputo, A Rumor of War (2014 Macmillan edition), p. 46 (Google preview)
The Paranoids were singing, to the tune of ‘Adeste Fideles’: […] grabassing around, trying to push each other over the side.1966 March, Thomas Pynchon, The Crying of Lot 49, Philadelphia, Pa.; New York, N.Y.: J[oshua] B[allinger] Lippincott Company, →OCLC: