What's "knock to a noodle"?

Native speaker’s answer
Rebecca
In informal terms, "noodle" refers to a person's head. We can understand "Junior takes a knock to the noodle" to mean "Junior gets knocked on the head." Ex: Junior has a big noodle, so it's difficult to buy hats that fit him. Ex: Junior's parents always joke that he was dropped on his noodle as a baby.