Wikipedia has an "Index of Human Sexuality" with hundreds of entries related to sex, gender, and sexuality.
For this game, pick something you've never heard of (hopefully something absurd sounding) and describe it here while linking to the article. Perhaps we'll all learn something, and hopefully we'll all laugh a little bit. There are hundreds of entries, perhaps even thousands? There is no obligation to go through this in alphabetical order! Be inspired by the letter of your choosing.
I'll start. I had no idea what "sanky-panky" referred to. I know now ;) The term refers to a male sex worker in the Domincan Republic that solicits on beaches!