When trying to get the best mobile phone deal, you ask for your pac code to be sent and threaten to switch networks in the hope that they will give you a better discount.
Fran: "Michael they wont give me unlimited texts unless I sign for 24 months..."
Michael: "Give them a Pac Threat"
Fran: "...and they're saying £35/month too"
Michael: "Pac Threat"
Fran: "I'm getting my pac sent....wait she's checking with her manager, yup I got it!"