How many girls has he actually done it with? At least early on the story it seemed like with some of them he was only doing the black magic knowledge transfer ceremony that doesn't include actual penetration.
The only one I'm sure he's actually done it with is just the succubus, the dream...
@Lioslin It's not that she felt bad about using the knowledge, but that she's being praised so much for it(being amazing etc) when she felt like she was just repeating what she learnt on earth.
Ah so it was 斗转星移, referring to the skill from Demi God and Semi Devils (I think they translated is as Star-Shifting Technique in some versions of the book's translation), instead of the Star Sucking technique from Smiling, Proud Wanderer.