I couldn't do it. If He asked me to, He wouldn't be Him. Even if I wanted to obey Him, I don't think I could.
Now if He insisted- I could probably bring myself to Domme someone else, but it would be a bit tricky, just because I am a sub. But with Him, our roles are very strongly ingrained in my mind, and I don't consider it a "game", so I cannot just switch it around for fun. It would be like turning my world upside down. I would be very confused and upset.