i own one - i use it as follows
20 minute drill where i repeat different moves like armbar, pancake reversals, triangle, etc etc
i hang it up from the ceiling and weight the feet down and do combos - boxing. MT, amd lota of single and double legs.
practice new moves from the class before
remeber this is supplimentary but very benificial, get to class and practice your shit here.
I have the OK blue dummy
http://www.trainingdummies.com/delux.shtml i bought the 50 lbs version