A flower boy is a boy who both looks and acts like a girl. They tend to have feminine habits, such as wearing makeup, and will also be much prettier than any girl you will ever see.
Girl 1: Have you ever seen Ren from Nu'est?
Girl 2: He is such a flower boy.
Girl 1: I know right! Why can't I be as pretty as he is?
After you secretly scratch your bare asshole you tell your friends how weird it is that your fingers smell like flowers. Then when they take a whiff, BAMO!, they get a first class sniff of what your ass smells like.
"Dude, thats weird, my fingers smell like flowers." "Really?" "yeah check it out."
"OH, DEAR GOD!!"