When it comes to artists that try to get in those "wow that was fast" first lewds, it's rather probable that they actually have a few "blanks" of generic sex scenes with mostly-finished models where they just have to draw the face in or add in a couple distinguishing features. Just have a few different ready-to-go blanks for different body types (loli, flat, busty) or major hair differences (long or short), then you're ready to just draw the face and color the hair within hours of the character being revealed, and your art gets to be "FIRST!"
