LMFAO (which stands for Laughing My Freaking Ass Off) was an American electronic dance music group duo active from 2006 to 2012.
"Party Rock Anthem" was a huge hit in many countries. It was even the best-selling single of all time in Australia.
One of the main lines of the song is "Everyday I'm shuffelin'". Shuffle in this context means a dance move of moving your feet back and forth quickly without lifting them far off the ground.
As the line is characteristic for the track, Rick Ross accused LMFAO having produced an unauthorized derivative work of his song "Hustlin'" which has the line "Everday I'm hustlin'".