Weekend immune system 

Another way of saying drunk and/or hungover. Owing to alcohols ability to suppress the immune system and the fact that it is usually drunk in largest quantities on the weekend.

Ugh yeah I'm not going to be able to come in to work today, I have a weekend immune system

Weekend immune system by lusciouslucas February 11, 2019

Weekend immune system 

Hungover/dead in various parts of body

Weekend immune system got me dead

Weekend immune system by rootentootenputin February 24, 2019