A, Uhm
It's like 'uh' and 'um' stuck together, but it can also mean 'you horny mate' if you're dumb enough to say it.
A: Uhm... I think I just peed my pants. B: You're not alone.
A: Uhm... I'm not your friend. B: You're not my friend either.
A: Uhm... you're a complete ass. B: Thanks, I needed that.