When something is f*cken awesome, excellent - something goes your way or goes to plan! "Double Pump" is said with one fist clenched, one arm movement, extend out and then is brought back into the chest. Twice, hence the "double pump"
Angie: "Hey that band Douglas Fir are playing at The Alley tonight"
Lizzie: "Ohhh awesome, Double pump"
(must include the action)