What is with guys and getting overly affectionate with each other when they’re drunk ?

Whenever my BF and his friends drink, they’ll get over affection

they start hugging and doing karaoke together and dancing and telling each other “you know I fucking love you man, I don’t tell you enough but i’m so happy I have you in my life “

and when they’re sober, they don’t let any opportunity slip to make fun of each other.