The placement of ones hands on their partners buttocks, the spreading of said partners cheeks, followed by the rough application of ones phallus to said partners anus - without the use of any lubrication.
For example the Australian men's Test side v the Black Caps batting line up @ the Basin Reserve, 1st March 2024 - " Jesus lads, we're getting absolutely gapped here.
When a women's vagina is very very loose, it is said to be 'gapped out'.
This is sometimes the result of genetics, however, it is much more commonly associated with whore-ish behavior; slutting around like a hoebag, banging dudes like a dirtleg, getting blown up like The House of a Thousand Cocks, etc.
The gapped out woman may have trouble keeping tampons inserted, or may be unable to tell 'if it is in yet'.
I finally banged the officeskank - that slizz was so gapped out, it felt like throwing a toothpick into a volcano.