boy, oh boy—an exclamation used as an expression of a range of emotions such as excitement, surprise, etc.:
- So my friend, Krista, came for a visit last week and boy-oh-boy was I ready for a vacation!
boys will be boys—is used to say that boys or even grownup men are expected to act noisy or misbehave:
- Well, boys will be boys, you know; we were just the same ourselves when we were young.