I crack both my elbows all the time. It has been a bad habit since I was about 11 or 12 when I noticed it. I always had a theory that it started because I was a cheerleader all my life. I think the over-extending all the time caused this. I can crack them VERY loud and a lot of people think its disturbing. My mom hated it and wouldn't let me crack around her.
I can crack both of them just by shooting my arms out but I get a more satisying one when I exend them realllly slowly then twist my forearm. I can crack my right elbow one extra way by putting pressure on it. Yeah I know it is very weird. I can also crack my right thumb a lot. I developed that one from writing in school and using the pen putting pressure on my thumb. Actually, I think cracking must come from the joints that you constantly put more pressure on than others. However I think it can be learned this way also.
I am the only one I know that can crack my elbows pretty much at will. I think I attempt cracking every 5 minutes or something, and after a while I felt like I looked stupid always flailing my arms so when I am somewhere I can be easily noticed, like at work, I use the slow extend way so I look like I am stretching and not constantly throwing my arms all over. lol :oops: