“Finger banging” (or “finger bang”) is a slang sexual term that refers to using fingers to stimulate someone’s genitals, usually meaning penetrative touching rather than just touching on the outside.

On Married At First Sight (MAFS), the “finger bang” or “finger banging” talk is about one couple sharing that their intimacy had progressed, but they hadn’t had full sex (“we didn’t bang”), and another cast member crudely turned that into a joke by announcing to the group that the couple had “finger banged.”

Because of that, the term is being used on MAFS as:

  • A reference to a specific sexual act between the couple.
  • A kind of immature, public punchline about their private sexual progress, which is why it blew up as “finger bang gate” and upset people on and off the show.

So, in short: on MAFS, “finger banging” means sexual fingering, and the drama is about someone loudly and disrespectfully broadcasting that detail as a joke. Information gathered from public forums or data available on the internet and portrayed here.