In the Ali Azimi video that I posted yesterday, there are some great examples of beshkan. If you have Iranian friends (although I don't think this is unique to Iran), you are probably already familiar with the somewhat peculiar way that we snap.
Beshkan بشکن comes from shekastan شکستن to break. So beshkan is the command form, or break!
Check out this tutorial on how you can beshkan Persian style. Remember,
اگر خواهی شوی خوشنویس بنویس بنویس بنویسagar khahi shavi khoshnevis, benevis, benevis, benevis, if you want to be a good writer, write, write, write, or "practice makes perfect". The more you practice, the less your fingers will hurt and the louder your snaps will become!