fatal first piss 

The first time during a long drinking session that one has to finally answer the call of nature or take a piss. This is a bad thing as this generally signals that there will be the beginning of many frequent drink-interupting trips to the dunny.

I held on as long as I could but after five beers I had to take the fatal first piss.

fatal first piss by Busted Hyman July 6, 2006

First Fatal Piss 

The first piss you take on a night out that opens the floodgates and makes you need to go every 8-10 minutes.

Lucy: Oh crap I need to take a first fatal piss
Dom: haha unlucky

First Fatal Piss by partyboy123 March 26, 2008

First Fatal Piss 

First Fatal Piss or FFP.
This happens when you're drunk and you have to go to the toilet for the first time. Because lets face it guys, once you go the first time you have to go again and again... and again.

Mira: Where's Hetty gone?
Charly: Oh she's having her First Fatal Piss.
*10 minutes later*
Charly: Hey have you seen Hetty?
Mira: Yeah, she had to pee again.
*30 minutes later*
Meg: Hey do you guys know where Hetty is?
Mira and Charly: Yeah she's in the toilet.

First Fatal Piss by iambethany December 23, 2006