I want to mock my girlfriend's ex
Really? Why would you even want to contact him?
He was rude to me once.
It is rude to insult someone and act petty. You should ignore him and enjoy your relationship.
I better do it soon. Who knows if he starts to talk shit about her.
Hey man, you got the girl, you should act like the bigger man and not let him bother you. She wants to be with you not him. If you start drama it might be a real turn off.