Place it at the very end of the rescue or favour, after the action has finished, so it acts as the closing thank-you. Follow it with a funny laugh to underline the irony, or a drum sting if the favour was deliberately absurd.
About this sound
This 2.6-second clip delivers the Portuguese line 'Obrigado, amigo, você é um amigo' in a bright, cheerful cartoon voice. It feels warmly grateful and playfully over-the-top, like a sincere thank-you turned into a joke. The line comes from Pica-Pau, the Brazilian name for Woody Woodpecker, and is widely used in Brazilian memes.