[ six tries to work out how rokurou went from point a - asking about whether or not he can cook - to point b, wondering if he knew when his birthday is. his head tilts because he can't make sense of the transition, and he supposes there's only one way to find out how they even got here. ]

... No. I've been met with disgust ever since I was born so I didn't know it was customary to celebrate one's birthday.

[ he puts his empty cup down. ]

Even if there was a date, it is long forgotten by now.