1. Get drunk and lock him out of the bathroom while you throw up. Scream through the door, "you're not my boyfriend!"
  2. Casually/excitedly tell him about this guy you just started dating. Say you think you might want to be exclusive with him. Then giggle like you're embarrassed about the term "exclusive" and not just uber uncomfortable that the guy you're talking to wanted to take you plant shopping.
  3. Invite him to brunch and speak vaguely about "timing" until he gets bored and leaves.
  4. While you're having drinks, get up to go to the bathroom and never come back. Leave some money on the table though for your drink, otherwise this is a real dick move.
  5. Pretend like he's your last real boyfriend and derive great catharsis from saying all the things you should have said in that breakup.