Two people who, by some divine intervention, always feel the need to pee at the exact same time.
Person #1: Ugh, I had too much beer, I'll be back.
Person #2: Where are you going? I'm gonna go pee.
Person #1: OMG I need to pee too!
Person #2: You're my Pee Buddy!
A friend in which they may accompany you to the restroom in case of any potential danger.
D:I have to go pee.
N: you need a peebuddy?
D:yeah will you come with?
The assigned friend who helps you in the bathroom when you are too drunk to do your business by yourself.
Amy: Who will be my pee buddy tonight?
Mostly used in the military for personal going to urinate but can not do so without another person to cover his 6.
PVT Joe:Drill Sergeant can I go to the latrine?
DS: Do you have a pee buddy?
PVT Joe: Umm, Umm, Umm
DS: (shouts out loudly) WHO WANT"S TO BE PVT JOE'S PEE BUDDY