Fai of course reacts in a completely dignified and mature way to this. Which is to say that he screeches, flails, and falls out of his bed - and sends a blast of undirected Psychic energy at whatever it was made that noise. Careful with that, Yuui, it's kind of super effective against Ghost types and all that. Also, he just tore away a huge section of the wallpaper. Elegant.
He is bad and should feel bad
"What the fantailed Fletchinder was that?"