To take a potion or elixir in a mmorg that doubles your experience points for a limited amount of time, and then push through to the end with little or no sleep to maximize your investment and leveling up capabilities.
The phrase is semi-popular among Dragon Age Legend players, and named after former DAL player Faren Longstaff who was notorious for doing it, and then going straight through to the finish.
Hey Mike, Lex, I got my elixir, my grub, and two dozen energy drinks. Now I'm going to Longstaff it and grind the Coves for xp and go from level 30 to 35 in a 24 hour blitz. Why don't you come and join me online.