I recently had a lucid dream where I possessed a DC. To do so, I jumped at the DC while shouting "Possession!" After the experience, I came up with an idea, which is basically as follows:
A dream power may be easily triggered by performing a motion associated with the power while verbally naming the power.

I have only had one chance to try this, but I feel that I may be on to something. Those who are reading this, during your next lucid dream, please try this technique with any power of your choice and post your results here. This may be very helpful to dreamers who can't seem to use their powers (like me).