Hello! I wouldn’t say I’m an expert at drawing nsfw or anything since I only really started a few months ago but I’d say don’t be afraid to use any reference, like not just reference for the pose, try to find references that showcase’s movement in the muscles. For me personally I read a lot, whether it be manhwas or fics so you kinda get to see how artist draws or describe certain angles and positions. For me personally I usually do have an inspiration and image in my head already when I wanna draw, I use 3D models to help to have a clearer vision of the image I wanna see then you just change it to your liking when drawing. It’s mostly what you find interesting and try to draw it out, studying muscles is also a good way to start! Hope it helps🥹🥹