The only time we see Mal and Geoff working together is when a sleazy former business partner comes to the restaurant in hopes of buying it off Tanya. Mal and Geoff then decide to lace his desert with an extra ingredient. JoJo and Tanya's reactions are priceless.
JoJo: Whose fucking jizz is it!?"
Made even more funny when the business partner likes the desert and calls it "divine".