I'm guessing the joke is that 老师 (teacher) implies an older person (the characters literally means old master) so Moke is insisting he's a 帅哥 (young man/handsome).
Updated
"可愛"
Note: These are the same characters used in Japanese as well......Thank you*bluussh*WoooowWaaaaaTeacher Moke is a young man!!a "young man"!I'm...HUH?Super cute!!Teacher Moke is very cute!WaaaaaCute!Cute"Kawaii" in Chinese is...