The act of hiding a portion of your chips in a pocket while playing l Poker then going 'all in'. Then, after you lose, taking the concealed poker chips from the pocket and placing them on the table like nothing happened.
Used to describe an activity which involves one person looking to have relations (sexual or intimate) with a minor.
Originates from the word nonce meaning pervert
Jeffrey: Hey Andrew, want to go out noncing with me and Ghislaine?
Prince Andrew: Well, I was going to go to Pizza Express in Woking, but sure, why the heck not.
When you, as a younger man/woman/whatever, groom an elder gentleman/gentlewoman/gentlewhatever into pursuing yourself despite their moral objections. Hence turning them into a nonce.
Person 1: Did you hear about what happened to Lewis?
Person 2: Ali, through reverse noncing, got him into bed
Person 1: No fucking way, Lewis is like 10 years older than him and not into younger men.