Firstly, wtf is a “peenar”, speak English.

Secondly, nobody cares, you shouldn’t either. That’s probably easier said than done, but time will teach you. It’s mostly just a trope. In my experience people say “mine is bigger” as funny banter amongst friends when they’re having drinks. Some people do actually mean it, but those are not the kind of people you want to be friends with. I only say it sometimes as my last argument when I’ve lost a friendly discussion.