Whoopsie, made a oopsie vampire-san •o•
This chapter has me putting a bit more stock in the theory that Wakana is just pretending to be enthralled. I could see Ruruna being saved from this "legal" situation by Wakana revealing she's in control of her actions.
I still have strong speculations about that theory, especially in this chapter. Wakana was enjoying the master play more than usual this time. Another point to add to that theory is that since Vampire-san is still a newbie when it comes to sucking blood from humans, she doesn’t really know how a human should act. There’s a possibility that, for Wakana, the effect wore off, and she just started playing along because she’s kinky. But then again thats just a theory ¯_(ツ)_/¯