I'm having trouble with backside boardslide. I tried it a couple of months back, but fell of onto my ass and since then have been deadly afraid of rails.

Anyone have any tips?

same problem here im still waiting help from someone on boardslides

i was told to throw your weight forward so you dont slip but it seems i slipped forward onto my nads instead of backwards onto my tailbone =[

Ride almost paralel to the rail/block at a comfortable speed, pop onto it so that your board is slightly over centre on the rail, or if its a block you want most of the board on the block.

Stay over the board, if your going fast enough you wont need to lean back to make it slide as momentum will do that for you, get ready to turn your shoulder as you come to the end and kickturn off the end of the rail to regular or fakie (its up to you) If its a block/bench/ledge your sliding your front wheels will be in contact with it while you slide so the trick is to sort of push the slide as if your sliding your wheels to slow down at 90 degrees. As you come to the end of the block slide your wheels to come out regular and roll away.

Once you have got that down start playing around with different ways of getting into it and out of it and popping out early to reg/fakie mid block.