A nap that you take before you go out to the bar/dancing so that you'll be more awake and have the energy to party more!
friend 1: "Hey what time should we meet... 7:00?"
friend 2: "No, better make it 8:00... I need to take a disconap first."
friend 1: "Hey, it's getting late; do you want to leave soon?"
friend 2: "Hells no! I took a disconap earlier, so I'm good to go!"