I can't speak from real life experience, but one movie that actually handles this really well (as far as I can tell) is The Quiet Man, during a fight.
There's an example of an impromptu, casual bet between two individuals who are understood to trust one another, where they actually set the odds and agree formally, and it all happens very smoothly and naturally so as not to be boring:
"Five to one on the big chap"
"Given or taken?"
"Given"
"Taken"
Handshake
IIRC, they don't actually show them agreeing on the wager itself, but a later scene shows the outcome and lets you calculate it for yourself. These characters are established to know one another, so I figure they either have a known amount between them that they default to for casual bets, or they just determined that off camera.
There is also an example of the more chaotic, mass, unplanned betting, where a character who is already established to be a jack of all trades known to the community pulls out a notebook and takes on the role of bookie. I think they even show the odds being adjusted in real time as the fight progresses, but I don't recall for sure.
They might both be right. I know my exposure to hate speech and bot-like activity decreased since I stopped engaging with that platform.