A phrase you say when something happened to both you and someone else, but it happened to you for a longer period of time. Such as if it took you 3 hours to do something and some else comes up and is all like, "Yo man, the jive took me like 2 hours to do, I was worken on that forever." You then would say, "Me for longer".
It also has relevance in skateboarding and surfing such as if you slide a rail or ride a wave for longer thn some one else. You win because it was you for longer.
Dustin and Justin were talking about how they both went out with the same chick, but since Justin lasted longer, he called, "Me for longer, fool".