Take a walk to Poo Park

Go for a shit/dump/crap.

Laurie: I got a real bad pain in my stomach.
David: Sounds like you need to take a walk to Poo Park buddy.

Taking the poo

Takin the poo in the UK is used when u are kidding

-That’s a donkey!
+no.. it’s a cow
-I know, i am just taking the poo