The act of doing a backward summersult and in mid flip grasp onto your partners neck with your legs releasing a fart into your partners face. As you Fart your partner sucks in the fart.
When one fist is shoved wrist deep in the Vagina, and the other is likewise inserted into the anus. One then proceeds to lift the recipient into the air with both fists, the recipient thus becomes the human flail.
Bro1: Bro, my girlfriend and I tried The Human Flail last night!
Bro2: Dude, no way! How was it?
Bro1: It was great! Arms, legs, and titties were everywhere!
Boys who enjoy yaoi (a genre in Japan that contains sexual and/or romantic relations between two men); literally translates to "rotten boy"; corresponding female : fujoshi