It's probably going to be difficult with the pedals/cranks rotate around especially if the back end of your frame is short, like it is with most modern frames. I'm not sure if I would be able to do it on my bike if it had a cassette, the pedals would probably spin into the back of my leg that is standing on the peg. It may be possible to position and contort yourself so that the pedals/cranks can rotate freely but this is going to be extra difficult.
You could always take off your chain whenever you want to practice them, then you won't have to worry about your pedals moving whenever the backwheel rotate backwards. This could allow you to practice while saving up for a freecoaster.