piss on

verb2

1. •
   (slang, vulgar) To express contempt and disrespect for someone or something, or to act accordingly.

   • You just completely pissed on my job performance here.
   • If you cancel this contract, you're basically pissing on me and all the work I've done for you.
2. •
   (slang, vulgar) To reject (a person, an idea, etc.)

   • She wants us to work outside in the dark? Piss on that. I'm going home early.
   • You've done nothing but complain the whole time we've been here. Piss on you. I'm done listening to you.