nariman, either you made up this story, or you are just as dangerous as your instructor....
You do understand the implication of what you said here... "Just that one of the engines is set to "simulate" the drag of one engine inop " makes it even more dangerous... especially if it did roll over on its back if it did stall.
If you did this and thought it was normal, your a fool, dont talk to us here talk to higher level instructor in the school. If it is all something you made up(which I hope it is) I hope you have learnt how dangerous this is.
Question look for single engine stalls and flight below Vmca in the your flight manual, if it says its ok to do it go for it (but I know it wont!) These books are written for a reason, and it isnt to fill pages with print!