laugh it up

1. To laugh uproariously, hysterically, or uncontrollably. Your jokes are perfect for your speech tonight. You'll have them laughing it up!

2. To tease or mock someone; to laugh at someone's expense. Often used sarcastically as an imperative. Yeah, I fell in the mud. Sure, go ahead, laugh it up! My so-called friends just love laughing it up whenever I mess up.