Dummy Reversal

Normally you should ruff in the hand with the short trumps, but use the trumps in the other hand to draw the opponents trumps. A dummy reversal is an unusual situation where you can make more tricks by ruffing in the hand with the long trumps.
I was asked in this video about dealing with bad distribution, and yes, this could be a problem if you get a bad trump break, and the opponents are able to then play clubs after you have run out of trumps. So a Dummy Reversal can be a risky play, as you are shortening your trump length!