The way you do a Birt Slide is by getting down on your knees. You want to make sure that your hand is extended out. If you're going to do a Birt Slide to your left, you want to use your left hand, of course. You want to make sure you don't get over-extended.
Once you have your hand on the ground you want to whip the back foot around so it's very important that you keep your weight on your front truck and whip that back foot around so that way you can get enough speed and momentum to land the turn. As soon as you're done turning, you want to hop back up.
Now, some people are able to do 360 Birt Slides. Some people like to do 180's. It's really up to you. Some people even like to grab the board as they're turning.
So if you have your right hand down on the ground, your left hand's going to be on the board kind of guiding you through that turn.
If you want to add a little extra style to your Birt Slide, you can go all out and grab the tail instead of grabbing the center of the board with your left hand. That will give it a little more flair as you're doing your trick and add a little bit more of an exciting accentuation to what you're doing.
So remember, you've got to get down low. You've got to crouch. You've got to time it. And make sure you put everything together.
So if you can do all these things separately, you really want to take your time, put them together, and then you'll have a Birt Slide.
And that's how you do a Birt Slide.