I don't let my mood swings stay for a long time at all. Most of the time, I listen to music or watch some fun or feel-good movie to uplift my mood. I even start keeping myself busier doing some productive work to get rid of the mood swing.
Music has been said to be a remedy for those looking at cooling off their mood swings. I have began the act of listening to music too when I feel a different type of emotions that I am finding difficult to deal with and it has been of great help to me.