A moment in your life that you regret so much that if doc brown from the movie back to the future came up to you in his time machine and said hop in its the one thing that you would fix
Groom: "You've got the rings yeah?"
Best Man: ...long pause... "errrrrm...hold on...errrrm..." ...longer pause... "yes"
Groom: "Thank F**k, I nearly had a brown pants moment"
Best Man: "Me too"
It is characterized by chrushing your sprit when you try on an article that you were excited about and it makes you feel the worst you ever have about yourself in your life.