Lyric discussion by fromadistantsun 

Cover art for AEIOU lyrics by Charlotte Sometimes

She's involved with a guy who's playing mind games-- flirting with other girls to make her jealous, sending mixed signals, generally being immature and pathetic. She hasn't given up on him quite yet, but she's frustrated and annoyed and she's telling him to put up or shut up.

Great song. I don't really get the AEIOU part, though.