When a sex scene is necessary, that means it is warranted by the plot and is the best way to achieve the effect the film is going for. I expect every scene in a movie to be thematically relevant.
There’s a reason I chose the term thematically relevant. The creator of that movie gets to decide what those themes are. Different things will work in that movie depending on what kind of movie you want to make. I don’t like or dislike sex in movies. I just want it to be there or not be there for a good reason.
I just finished season one of “The Boys” and they did a fantastic job of implementing “necessary” sex scenes and excluding or “cutting to black” on ones that aren’t. Just a few examples:
spoiler
They only show the lead-up and follow-up of the oral-rape scene with The Deep and Starlight. We don’t need to (or want to) watch the actual encounter because the important info is what led up to it and how Starlight reacted; the audience wouldn’t gain anything additional by watching the actual act.
However they do show the scene where The Deep gets gill-raped, because it’s weird enough that the act itself needs to be shown to be understood by the audience, and watching The Deep’s reaction to what is happening while it’s happening is important (the pain, the powerlessness, the confusion). Starlight realizes what is happening before the rape itself; The Deep only realizes while in the midst of it, because as a man/abuser he doesn’t expect to be on the receiving end of what he’s been remorselessly fishing out (autocorrect turned dishing into fishing and I’m leaving it).
The sex scenes between Stillwell and Homelander are weird and uncomfortable, but a respectable implementation of show-don’t-tell of their complicated Oedipal relationship (as we learn that during intercourse Stillwell treats Homelander like her young child, presumably as a calculated way to control him and secure the loyalty of an incredibly dangerous loose cannon). Given the theme of a child raised without a mother, and Homelander’s eventual murder of Stillwell, I accept the artistic decision to include scenes of their intimacy so that the audience better understands their bizarre relationship.
Generally the sex scenes aren’t titillating and don’t last longer than necessary to convey whatever plot/character development the writers want to reveal to the audience. This is another reason why I think their inclusion is highly calculated, and arguably “necessary.”
