Don't kiss and tell
None
Vincent did his best to keep Rosalie from falling over, though being this close to her definitely made him blush a bit, thankfully so far Rosalie hadn't noticed, or hadn't said that she'd noticed. He frowned slightly when she said she hadn't eaten, it was no wonder why the alcohol had gone straight to her head. After all the hype about the party and getting him to go with her, he was a bit surprised she already wanted to call it a night, but he was most definitely fine with that. The part wasn't exactly his sorta scene.

Sure thing. He hadn't actually noticed that she'd said 'we' can go to sleep, that was until she corrected herself and explained. That just made him flash fifty more shades of red and stutter a bit. Um, yea kinda figured, but I'm not leaving you until I'm sure you're OK, that means making sure you've eaten and drunk plenty of water before you go to bed, that way it minimises any hangover.
Rosalie nodded and allowed Lucien to take her to her rooms. She would soon move to her own house, since now she was no longer a student thus she had to leave the place where students stayed (they had allowed her to remain here for the rest of the month out of kindness)

The blonde ate, drank plenty of water and changed in her room, out of sight for Lucien. She trusted Lucien to know what to do in case of potential hangover thus she followed all the instructions before telling him goodnight and crashing in her bed, hoping to not be miserably hangover tomorrow.
True to his word, Vincent made sure that Rosalie was completely settled before he left, also making sure there was a bucket near her bed in case she woke up in the middle of the night and found that she had to puke suddenly. There was a part of him that didn't want to leave at all, but he imagined that sitting there watching her sleep would probably make the top ten things a creep would do list and decided firmly against that course of action. Once she was good and in bed, he kissed her lightly on the forehead and headed back to his room at the nearby tavern.