Before any action or interaction takes place between you and the woman, she presents two small cups of mouthwash, one for each of you. Then, just like proposing a celebratory toast, the both of you go bottoms-up, swish, spit, and rinse. It's done that way to show to each other that right then and there your mouths are at least that clean and your breath is fresh.
It originated in massage parlors featuring K-Girls (sex workers from South Korea).

toast with blueberry jam on the children's menu.  lol

Doing mouthwash during the Covid mess was a good idea in any event as a good rinse killed the virus, and who knows what else lurking in our mouths.

Dentist offices were told by the ADA to require mouthwash as part of the Covid protocol, but recently removed the requirement.  Too bad.