Hi there! So, let me explain what a stag film is. Have you ever seen grown-ups watching a movie together that's not for kids, like a really scary or grown-up movie at night? Well, a long time ago, when there weren't a lot of movies around, adults sometimes watched something called stag films together.
Stag films were movies that were only meant for adults to watch because they showed things that kids like you shouldn't see yet. They were usually shown in secret places like someone's basement or a club and were never shown in public theaters.
Stag films were different from regular movies because they showed people doing things that were private and intimate, like taking off their clothes or kissing or even more adult things. These movies were mostly made in the olden days when there weren't a lot of rules about what could be shown in movies, but now there are laws that make sure that kids like you are protected from seeing things that you shouldn't.
So in short, stag films were movies that used to be made a long time ago for adults to watch that showed things that were just for adults and not kids.