Are cousin marriages/hooking up common here?

I recently watched “How to make millions before grandma dies.” I really enjoyed it, but there was a scene one of the guys is staring at his cousin’s butt. Then she asks if he wants to join her onlyfans and that it’s not a big deal, they’ve kissed before. I’m just curious if this is normal in Thailand? I understand that in more rural and with old traditions that cousins might marry to keep the wealth in the family, but this doesn’t seem like that at all.