Is it permissible for me to obligate myself to fast three days immediately after watching dancing clips, or four days if I delay by a day, in order to deter myself from this habit?

What the questioner did is an oath of obstinacy and anger, its ruling is the same as that of an oath (yameen). If he does not fulfill it, he must offer expiation for an oath. He has the choice between fulfilling it or offering the expiation. A Muslim must obey Allah and fear Him, whether he has made a vow or not. His fear of his Lord should be greater than his fear of his vow.