Where you, or your friend, betray your friendship with others of the same gender to go and flirt with other people of the opposite sex (and commonly fail to pull).
"Oh look at Mobbsy, he is doing another Jono!" or "Doing a Jono again, Mobbsy?"
To do a jono is the act of rejecting your current company to maneuver, in a stalking fashion, over to a person of the opposite sex. Doing a Jono usually consists of a male, staring longingly at a female's chest area. This act if performed subconsciously and usually leaves the former company of the "Jonoer" feeling annoyed. Two people can subconsciously do a jono together, which is known as in the trade, Dual Jonoing.
Sarah: "(oh god, hes doing a jono again, i wish he'd leave me alone)"
Phil: "Oh, theres goes Jono on another tit rampage"
Bob: "Ah man, just leave her alone!!"
Jonoer: "breasts? breast breasts breasts breasts! hmph... breast!"