'For Your Own Good' by amanuensis1 is kind of one of those for me - established-relationship kink that's blazingly hot and subtly deals with why dom/sub works for this Harry and Draco. (Warning: you may find it 'too hardcore'. If so, please don't bother kink-shaming me; I've warned, don't need to hear about how my 'almost freakish' kinks made you cringe.) I know I've read others that dug into how & why bottoming/submission worked for Draco's character, but they're not coming to mind.