left

it really depends. Sometimes people slide differently if there right or left handed. Most coaches would have you slide right leg back, so your not facing the throw. However I slide with my left leg back, because I don't like not being able to see whats going on. Plus I generally do slide-by's and it really, really hard to do if you slide with your right leg back.

dose not matter but you realy want to slide you want your right leg because it is a faster jump

I Always Do Left..

It depends a) what base your sliding into & b) how you like to slide.