Is he perhaps laughing at the flying elf?

Xue Ren could come back to the elven world solely because Sex Goddess is dealing with her body being all hot and lustful as well. He had his own family being here, but as Sex Goddess wants to be his, she has to deal it on her own.

It's going to take a lot of time for sure in this case.

That's why, Xue Ren spend his time with Xue Yu, both of them feeling the immense pleasure as if made for each other. Xue Ren truly thought that she was born as his 'woman' and as such thought passed his mind, Xue Ren felt something trembling within him.

Was it a clue?

"Ahh! Daddy! No! Ahhh! I am! I am! Ahhhhhhh!"

If that's the case, then Xue Ren just had to push deeper. Thinking about Xue Yu as his woman only, Xue Ren gave her so much love and pleasure the seductress herself couldn't withstand it. Her eyes became blank from the pleasure, then as she slowly lost her consciousness, Xue Ren grasped her meaty body and used his own as a bed.