The large open space on the forehead of a gaper between the helmet (or hat) and goggles while skiing/riding. Also visible days after in the form of a sun burn or wind burn on the forehead.
Gaper: Man, my forehead got fried skiing this weekend!
Local: You need to pull your helmet down and cover your gaper gap.
My wife had a gapey after an hour of pounding my cock up her asshole.
The gynecologist could tell that her patient engages in a lot of anal sex because when the patient bent over on all fours to expose her asshole, the patient had a gapey.
The permanent slight opening of the mouth due to being overstretched usually by multiple dicks.
I decided to push the limits of the suck fest by wanting a third dick added to my mouth once that happened I felt my mouth stretch. Oh great, I ended up with mouth gape. Now I can't stop drooling.