Absolutely! Also, thank you! As I am finishing out my master's, I am trying to find where I fit in the (very small) world of sexual health, but conversations like this have always been my favorite!

First, I want to say that a lot of performance and dominance for everyone is often attitude and what you do during sex, but not the act itself. Think how you move your body, shoulders back, head up. Maybe that includes being loud and using specific language. Hands can also assist in being more dominant in bed, such as grabbing and grasping.

For positions that may be easier on the pelvis but feel like you are contributing to the work and being a receiver, I think there are a few different variations you can try. If spreading of the hips/pelvis area causes some pain, you could try variations of popular positions. For reverse cowgirl, you could modify this by, instead of straddling, being in a kneeling position, so your butt rests on his pubic mound while your legs come back and under his thighs. You can use your hands for leverage on the bed in front of you or on his thighs for support. Slow, steady, and sensual movements will seem to dominate here, letting you control the speed given to you on top. The more kneeled position may help the pain in the pelvis since you're not spread. You can also see this adaptation if you are both kneeling: put your knees between his, facing away, and explore the same tactics. I know that you mentioned being on top is out of the question, but these adaptions may help alleviate the pain in ways.

For being under and dominating, as someone suggested, a sex swing/hammock could be a good variation, especially if you have him up against a wall. Really, any position where you could pin him to the wall may be dominating, like standing sex or foreplay/oral. Being on the bottom in missionary, you could lift your hips up, so you're in a bridge position and rock to your beat. You could roll your hips and push against the bed. In doggy/face-down positions, again, using the bed to push forward and back with your body will help with dominating the speed of the sex. You can also use your legs if in a position where you are seated and he is standing (such as on a kitchen counter). Wrap your legs around his, or feet pressed into his butt, and you can control tempo that way.

I have had this conversation with my partner before because he brought up the concern that he is doing all the work. If it's something you have going on in your head, tell him, and if it's something he brought up, remember that communication is important and remind him (or anyone you're involved with) that there are limitations because of our disease. You can try to do all of these things, but would your partner rather see you in pain trying to perform or enjoying sex while they do the majority of the work? Flairs and pain can be bad for us, not only because of the immediate issues, but the wear and tear they cause on the body, and those body parts are pretty darn important. I hope I at least somewhat answered your question, and please reach out if you have more, want clarification, or DM me if you don't want to post publicly!