a term coined by @509cougar on twitter meaning You're Only Young Once, derived from Drake's YOLO. There are many things you can do in a lifetime, but only some can/should be done during your youth.
Michaela: girl, I'm not partying tonight, I've got too much homework to do.
Tiona: YOYO.
40 year old: Bro, lets go hit up the WSU frats tonight.
25 year old: um, dude, YOYO and ya time is up.
Adapted from the popular term YOLO (You Only Live Once)....what you really mean is YOYO (You are Only Young Once) so live it up to the fullest!
Your friend asks want to take one more shot,, and you respond no I'm too drunk, and he replies YOYO!!! and we take 2 more shots because we are only young once!