Quadbox MethodThis is a method to obtain 50 pimp kills with quadboxing.
Before you get this achievement I would recommend getting the Kingpin achievement. That achievement will be quicker if you always win (whereas this achievement you can save time by throwing some matches) and you will naturally get some pimp kills along the way.
1) Gather into two private parties with two accounts each. Start searching ranked Protect the Pimp with one party and wait for the silhouettes to turn white. Then search with the other. In my experience I found it easier to connect if my 2 dummy team went first and then my 1 main + dummy team searched after. Your results may vary. Once all 4 players are in, it will take another minute or so of the game trying to find players before the match will start. You can try playing at late night hours if randoms are joining.
2) If your main starts on the pimp team, you can have the other player teamkill the pimp for 2 rounds to get on the pimp killing team (these teamkills of course won't count for the achievement). Once on the pimp killing team, head out with your main to find them. They always spawn in the same spot depending on the map.
Airport: This one has the most annoying layout. The pimp killing team spawns in inside the terminals while the pimp spawns down a long hallway where the planes would be docked outside. Try your best to learn the best routes to get there from each spawn point as you go.
Offices: The pimp will spawn on the fancy offices on the top floor. Pimp killers sometimes spawn on that floor as well but usually spawn on the middle cubicle floor or the lower entrance floor. Again just learn the layout, it's less annoying than the airport.
Hospital: This one is similar to Offices with stacked levels and the pimp always being on the top (red) level. The middle level is blue and the lower level is green, make your way up to take him out.
3) If you didn't teamkill to advance the rounds at the start you can do so now. The 5th round is a toss up; you might be on either team, it seems random. If you're on the pimp team you can teamkill again for 2 pimp kills total this match. If you're lucky enough to get on the pimp killers you can get a 3rd.
Repeat as needed until the achievement is yours. Because of the shorter matches the leaderboards should update so you can check your progress under statistics > Protect the Pimp.