The most misunderstood gesture in your world?

Hi, I don't know how to open the post this time. But let's go straight in, I really want to know the gestures which are usually, or oftenly misinterpreted and misunderstood in your world, on both worldbuilding and story lore, and how you explain them to the readers. Like, it's either:

• normal in your world, but strange to your readers.
• strange to both your world and readers' view. And how it impact on your world

Like mine in my dark-low-historical fantasy world, Where Twinks Fuck, it is the small formal kiss on the bum inside nobility circles. In my world, it is described as:

"the kiss of no lustly desires, a symbol of respect, loyalty, grace, appreciation, silent lifelong vows, and in the times of death, is the symbol of reluctant, remorse and mourning before the depart of one's most beloved."

The bum kiss is considered as normal in WTF. It can occur between friends, uncles, brothers, lovers. However, some still doesn't understand the meaning of this kiss, and intentionally drive it into something...different (orgies et cetera...).

Bum kiss rarely appears in my story lore, but once it appears, it profoundly deepens the depth of characters' relationship - that their bond is beyond something more than just love.

Fun fact: I once watched Call Me By Your Name film in teenage hood, and the lack of scene(s) of Chalamet getting pounded in every possible angle marked a deep impression in my head till this day. That's why I put the kiss into my world, I just love it so much ❤️

Sorry for the lack of explicit details, I'm trying not to make my post too long 😅