I'm sorry but this guy sounds like a freak or even something worse. Sounds like he likes the power to hold your life in his hands. If your heart does stop in the process, do you think he will hang around to bring you back? As from reading your post I think not!
Get rid of him now before it is too late.
I'm serious: Dump him. This guy has a 'your life in my hands thing' that isn't going to end well for any woman involved with him.
Yikes! Oh, yikes!
Here's what medline plus and the National Institutes of Health have to say about giving chest compressions to a normally beating heart:
"DO NOT * If the person has normal breathing, coughing, or movement, DO NOT begin chest compressions. Doing so may cause the heart to stop beating."
http://www.nlm.nih.gov/medlineplus/ency/article/000013.htm
Jeez. Find a new, not-weird boyfriend.
I am pretty sure he can kill you by doing this. Everything I looked up said in a beating heart, cpr can actually STOP it. You need to stop this now!