An epic slapping together of hands by brofriends. Doesn't involve any other body parts, JUST HANDS! A guy five should hurt the palm of your hand, otherwise you aren't doing it right. Your hand should tingle for hours afterwards.
A guy five is done when something epic has happened, or when the excitement of life and brofriendship gets to be too much. Often coupled with a brohug.
Guy fives should be celebrated in society and performed regularly.
Levi: "OMG I just designed a new rug!"
James: "GUY FIVE!"
*Huge slapping noise reverberates throughout the world*
It's a high five that only men can do. Except instead of slapping hands together you slap penises together.
Guy 1: WOOO we just one the game!
Guy 2: FTW! Guy five?
Guy 1: FO SHO!