Since these tricks are all named from skateboarding I'll explain it from that point of view.
Frontside - Chest facing box on approach always, no exceptions.
Backside - Back facing box/rail on approach always, no exceptions.
Stright/ride on feature - drop the FS/BS name it doesn't apply.
Tailslides and Bluntsides are essentially the same trick but the difference is how you get into them.
Tailslide your back foot goes over/onto the rail and your front foot hangs off, you should be sliding on your tail or back foot. Back Tail your looking uphill, Front Tail your looking down hill.
If you jump your front foot all the way over the box/rail and land on your tail with your nose/board hanging off the other side of the box now were talking Blunt. Front Blunt your looking downhill, Back Blunt your looking up hill.
If nobody saw you get on the box they would not really be able to tell the difference (although diehards will tell you to be a true blunt you gotta raise the foot thats not sliding up higher than the one thats on the rail).