This technique should be used a limited amount of times, as there are several negative consequences:
1. The teacher or professor mistakes your stretching motion as you raising your hand and calls on you to answer a question. Which, of course, you can't answer because the question was posed while you were texting.
2. The teacher or professor becomes suspicious of you constantly stretching.
3. You accidentally wack the football player sitting behind you because you lean too far back (Trust me it's been done before and he does not react nicely).
Guy 2: Relax man, I'm just doing the cell phone stretch.