1. Whenever you eat ice cream with a friend, start singing "DO THE ICE CREAM AND CAKE! DO THE ICE CREAM AND CAKE!"
2. If your friends has a gold fish, put bubble soap in its bowl/aquarium. Stir it into the water.
3. If you friends has a gold fish, put goldfish crackers into its bowl/aquarium. When your friends asks why, tell them the fish were lonely.
4. When writing and e-mail to your friends, WriT lIKe DIs.
5. Introduce your friend and then say "She/he's the crazy one" <- credit given to CAITLYN_SU for that one
6. Sing The Song That Never Ends
7. When at their house, immediately open their fridge and eat whatever you like.
8. Show them this list XD
If you have any more ways, please write them in comments so I can use them in future articles.