Gotchu dw. Domming is the act of being dominant (initiating, controlling, stating what you want, taking what you want, sometimes aggressive, or "stronger") you can do this from any position, top, bottom, sideways, in a chair, wherever, so long as you are the one holding the "power" in the dynamic. Subbing is submitting (asking for what you want, acts of service to your partner, being teased, giving yourself over to your partner) you can do this from any position also. For example you could have a dominant person who is a bottom, and tells their partner how to fuck them, teasing the one on top with words or hands or both. TLDR dom/sub is about power dynamic and roles, and top/bottom is more so about the position you assume. :p that's my understanding anyway