Stag Film 

An X-rated film taken by a man of his wife or girlfriend having sex with another man with his permission

Your wife is hot, do you have any stag films?

Stag Film by SecretPlayWife June 15, 2018

stag film 

An old-fashioned name for a pornographic movie.

Made famous by Jack Warden ("Pops") in critically-acclaimed Dirty Work: "Nah, back when I was in the STAG films."

stag film by My name? It's Marc; with a "c" January 31, 2008