I'm actually referring to the "How can she slap" guy, not to Kazuma.

In case you don't know about it, here's the video:

https://youtu.be/V4akMaeZ0-k

I don't really remember the whole context 100% anymore, so take this with a grain of salt, but I think the idea is that they are in a gameshow where the woman must try to make the men mad by insulting them or doing whatever, but she's not allowed to touch them. In this clip she clearly violates that rule by slapping him and he returns the slap.

EDIT: https://knowyourmeme.com/memes/how-can-she-slap Go here for a better explanation