When you're playing marco polo with a friend and instead of yelling "polo", he/she yells "yolo"
I was playing marco polo with Jane yesterday until it turned into marco yolo...I was then forced to exit the pool out of sheer humiliation.
It's exactly like Marco Polo, except you play it in traffic.
*Fish out of swagger is anyone on the sidewalk*
Yo instead of doing the tide pod challenge, you wanna play Marco Yolo