Verb. To remove a prawn's digestive system during the shell peeling process.
A prawn (or shrimp) will normally shit itself when it realises it has just been thrown into boiling water or on a barbecue. Therefore after the prawn is cooked, and you peel off the shell, you will find a string of black stuff running down its back. This can be easily removed by digging the index finger in just behind its head, grabbing the black string-like thing and pulling down towards the tail. This is commonly known as "depooping".
Hey, did you depoop this prawn? I see black stuff !!