Extremely dangerous! Do not attempt! I will explain how they do it so you can avoid doing it by accident.
Just so you know, you should always travel with the bucket or attachment as low as possible to avoid tipping over the machine. Always wear the seat belt ( I have seen operators thrown out of the front of skid steers ). Also, go in reverse up steep slopes or the machine will tilt over backwards. Skid steers are back heavy so they tilt over backwards easier then forwards.
It doesn't take much to get a skid steer to tilt over forward. Just go forward at speed and then hit reverse with the bucket or attachment in the air. Or, put a load in the bucket and do the same thing but at less speed.
This is also extremely hard on the machine. There are stunt drivers that do this for shows but they have modified engines and machines. If you tilt any engine at an extreme angle you will starve it of oil and burn it out unless it is properly modified.