One of my best friends during high school decided to try the same thing. I'm not sure if he's a liar, but I don't think he is. He claims he didn't masturbate for 40 days. Tough kid if he's telling the truth.
I don't think there is any difference between CR and Orgasm Denial. They sound like the same thing to me. I've only ever heard this action referred to as Orgasm Denial... I had completely forgotten about the term "Cum Restriction!" Well, I suppose we increase our vocabulary every day, now don't we.