. Pull his hair all the time.
2. Replace all his hair ties with fluffy розовый ones.
3. Paint sparkly Бабочки on everything he owns, and on him.
4. Throw Еда around in his кухня until Ты can't even see the walls.
5. Tell Ryou that he poisoned the cake.
6. Actually poison the cake.
7. Put chewing gum in his hair.
8. Every day, sneak into his bedroom and hide a банан under his bed.
9. Keep doing this until he has a massive pile of rotting bananas under his bed.
10. While he's cooking, play really crappy music, really loudly.
11. Tell him Ты really really Любовь mash potato, make him cook Ты loads...