In the anime Mio falls under an aphrodisiac curse by Maria using the "Reversed" Master-Servant Pact which is triggered by the servant's Distrust to his/her Master
On Episode Five of the anime,
Following Yahiro's defeat, Basara wakes up with Maria lying on top of him while seducing him, encountering Mio naked in the bathroom while getting caught in an awkward position, Yuki offering herself to bathe with Basara, and Mio yet again falling into a pleasure-driven curse.
After the scene Basara lift Mio and said going to her room. The scene then is cut (eventhough its uncersored version) the nezxt thing they are eating at a restaurant. so what happened in between these scenes.