I'm pretty sure this is a reference to that chapter in Tonikaku Kawaii where they said it would be super embarrassing if they were seen kissing at night in the park or something
Yeah I knew What'd be topic of the comments so I came to see.
Well it's no wonder. All of his works are on his own universe. Let's say hataverse. Hayate no gotoku's mansion and Maria were also showed in Tonikawa