I think you're going about this the wrong way. From a pet training standpoint, you're trying to mitigate the consequences of the bad behavior, instead of stopping the bad behavior.
1. Buy broken version of your model phone off eBay for $5.
2. Rig it so it'll fall apart when dropped.
3. Pull it out of your pocket as if you're going to send a text.
4. When your "friend" goes to grab it, pretend to fight him for it, and allow it to drop to the ground.
5. Pick up the broken phone off the ground, and proceed to go ape s#!t. Rant about how he always does this, and it was just a matter of time before an accident like this happened.
6. (Optional) Guilt your friend into buying you a new phone.