Sorry, dudes, nothing to see here. Everyone keeps their clothes on, no one talks about sex in any way, and even the engaged people don't make out or anything. Shoot, the married people don't even seem to touch each other (although obviously something must be happening for Tzeitl and Motl to be having all those babies, not to mention Tevye's seven daughters).
After all, we're talking about a culture where weddings (weddings!) are celebrated with women on one side of the room and men on the other, with a big old wall in between.