An adlib commonly used by mainstream and underground rappers that imitates the sound of a car's tires screeching on the road. They use it to fill in specific gaps in bars in a rap song.
It is used to show that you are the coolest kid among all our kids. It is used by every kids in the world. You can just say skrrrt when you meet someone.
Coolest kids: skrrrrrt skrrrrrt skrrrrrt skrrrrrt
Other kids: holy smoke, dat kid is freaking skrrrrrrt, damn, so fking cool, I want to be his frrrrdd.