|I'm glad you pointed out the differentiation between slams and bails. I am so tired of seeing videos posted online where skaters say they bailed, when they actually slammed.
I am a white anglo saxon, and my terminology is thus :
1) Slam -► Uncontrolled crash; includes trying to bail during, or before the trick, if unsuccessful bail results in an uncontrollable crash.
2) Bail -► Successful attempt to either disengage from trying a trick, or to recover during a failed trick, to avoid crashing. Result - rolling away unharmed, and not falling down.
There are some mixtures of the two, but is a crash results in any way, then I'd call it a slam.
: Obviously, you want to bail rather than slam. As everything else, this has to be practiced. It's easiest if you have someone around who is proficient in good bailing technique, because he can watch you and give corrective advice. In the beginning, inline magazines propagated six-point falling techniques which looked ridiculous to experiences skateboarders but where sufficient to prevent serious injuries. The technique just wasn't very elegant but an OK starting point. You would land on your toes, knees and palms and slide it out. When you got more confident, you could put your weight behind you and only slide on your toes and knees. On roller skates, there is a variant which skiers call telemarc-style (I'm not a skier, obviously). In this variant, you'd slide on only one knee, while still rolling on the other skate. Often you wouldn't slide it out but stand up again and push up the ramp again, thereby losing much less time.
: In videos not every fall is a good role model. Often, there is a slam session included to show off the hard falls the skaters in the video have survived. You shouldn't try those at home.