"Your Majesty, you didn't dig up something strange and eat it, did you?" "What do you think I am?"
"Midnight tryst" is probably the best period-appropriate translation, but from everyone's reactions I think the most accurate translation for "yobiai" might be "booty call." Oh, Ryuuki.
I wish there were more women in this series, but I do like that Shurei is sincerely more interested in a career than romance. Poor Ryuuki, though.
I am completely at a loss as to why Kouyou is convinced Ryuuki will make a great emperor.