-Do you feel the urge to dom and sub a single person at the same time? Maybe at different times during the same scene?

Nah, once I'm in subspace there's going back and the rush of being dominant generally takes over when I'm on Top. Towards the end of a scene where I'm on Top though, as we're winding down, I tend to get a little submissive feeling.

-Do you dom and sub at the same time, but with different partners (I'm a sub for this person, but a dom for this person)?

Nope but it's a fantasy of mine.

-Do you take turns with your partner (tonight, I'll be the boss, tomorrow night, you be the boss)?

Generally over the course of a night we'll each dom the other once.

-Do you feel like a dom/sub for long periods of time, then feel the need to switch again (i.e. feeling like being the sub for weeks/months/years then kind of feeling dom-my for awhile)?

I really can't pick one over the other for an extended period. I like them both too much.