The act of Cocoing someone refers to the act of dating / shagging / kissing / having any form of sexual relationship with them despite the fact that they are much much younger than you.
The name is derived from a legendary Cocoer called Coco who preyed on young girls during 2008 / 2009/
Guy 1 : "I know that girl is young but I would love to ejaculate inside her"
Guy 2 : "Dont be such a Coco"
"So what if my girlfriends only 8 years old, theres nothing wrond with Cocoing"