The sidearm flick was the hardest for me to learn, and definitely took the longest. I guess this just shows how everyone is different - some people learn that one first, and think it's the easiest!
Anyways, it sounds like you're having the same problem I had with the sidearm.
First, keep on doing it the "dragging off the ground way" (like in our video) so that you can continue to develop a feel for where the crack happens, how straight forward the whip has to move, and when to give you wrist the little flick at the end.
Second, what it sounds like is happening is that when you're pulling the whip behind you for the "wind-up," it's not going straight behind you. Sounds like it's going behind you then continuing to cross your body while it's behind you (which is why when you try to bring it forward, you're trying to pull it through your body so of course it's going to hit you in the back or the head). The thing is, I
know it feels like you're pointing and dragging the whip straight back, and not angling it... but it sounds to me like you are. How to fix this? First, go really REALLY slow, and actually turn your head (not your whole body, just your head) so you can watch the tip of your whip as you are swinging it back. Try just doing the swing back "wind-up" without pulling it forward first, and make sure the fall isn't crossing over behind your back when it's behind you. Then when you're satisfied you're doing it straight (still all the while keeping your eyes glued to the tip of the whip), go ahead and pull it forward.
There was a period of a couple weeks when I was first learning the sidearm crack where I could only do it without hitting myself if my head was turned so that I could watch to make sure my wrist was pointing the thong straight behind me. But having to turn my head every time was starting to drive me a bit nuts (not to mention I was sure it didn't look cool), so I had to figure out a way to make my wrist (and therefore the whip) behave without my visual supervision. What ended up working for me was tricking myself. I concentrated and told my arm and wrist to point the whip behind and angled a little bit
away from my body on the "wind-up." I figured that if my wrist interpreted "straight back" as "angled slightly behind and across my body," then maybe it would translate "angled slightly away from my body" into "straight back." Well, it worked! And in time and with a lot of practice I stopped needing to trick my arm into doing things or supervise it... muscle memory is a wonderful thing.
I hope that helps you a little bit. I remember how frustrating not being able to get that darned flick was!
Also, if you want to be ahead of the game, I'd definitely suggest working on both arms as soon as possible. But I wouldn't worry about one arm becoming massively more muscular than the other unless you practice
several hours a day, lol. Once you get better at cracking, you'll notice it becomes much less of a workout...
Good luck, and have fun. If anything I wrote doesn't make sense, just ask me and I'll try to clarify or re-word it.
Lauren Wickline
http://www.midwestwhips.com