Stand in split stand, one leg before the other
Hips square
Front leg with heel on a slider, socks or towel
Rear leg on bended knee, unactive foot behind
Slide to the front with your frontleg but only as far as you're able to pull yourself back and up again by engaging your rear leg.
Do this without or (if you need it) with something to help you hold your balance, like two yoga blocks
Don't bend your upper body forward, always keep your shoulders above your hips, your arms should hang relaxed besides the hips (or the aid for balance should be at hip height), not in front of them
5 - 10 times
10 -30 sec hold