***This solution is for those without the DLC content, and is proven to work the BEST******
I found the BEST method of boosting to get this achievement. My method does require 1 other (at least thats how Ive done it). Im sure with at least 1 more person it can go alot faster. But sign into Xbox Live and play a Player match later in the night when not alot of people are online. I was able to boost with the other person entire rounds of Dog Pile or Team Dog Pile depending on what others online are not playing!!!
Now take turns were one player gets all the kills in a 10min period. I just stood in the turret the entire time where the other person collects the bone (You must wait for him to get the bone each time)
Now you kill the person carrying the bone the entire match. You get +15 points for every time he is carrying the bone. After the 9+ killing streak you get Doghouse and get a Bonus too! Now here is where the BIG POINTS come. After DOGHOUSE every 2 kills you get after, you will get a +35 points for every kill!
At the end of a 10 min period, I was walking away with 950+ points each match without even trying and the other person still got a total of about 200+ points! Then rotate killers once the match is done
You will get this achievement in No time at all this way!!! A total of 25,000 points in needed for this to Pop