You see: You flail your arms about. Others see: <Person> flails her arms about.
FLAIL <self> You see: You wave your hands in front of your face. Others see: <Person> waves her hands in front of <his/her> face.
FLAIL <person> You see: You wave a hand in front of <Person>'s face. Target sees: <Person> waves a hand in front of your face. Others see: ?