Happy birthday to you, you look like a ball, can’t fit in my jaws, I try to suck it.
Birthday Ball
Explanation
Explain Bear
Alright, listen up, you knucklehead. The joke is that someone is comparing the birthday person to a ball that they wanna suck on but can't cause it's too big. Bet you are the kinda guy who claps when the plane lands. Sheesh.