Yazeno misses her so much, after all, it's been more than a year since the last time that he had intimate contact with her. That time when she was unconscious after graduation.
He locked the door just when she was already lying on the bed. He goes to the bathroom and prepares a basin with lukewarm water to have her clean. He took off her jacket that was given by Cailly earlier and wiped her arms and neck and face. He peered at her pants and didn't dare to remove her clothes. When he was done he took the basin back to the bathroom and left her alone for a minute and took a bath himself in his room.
Although he drank a lot of the wine. The difference between him and the other two of his biological siblings that were brought knocked out after a glass or three of alcohol is that he took all their tolerance on alcohol. Meaning even if he finishes a bottle of rum or vodka he will not get drunk but just tipsy.