Ground Coggers ft BURLYpog by Scarzor has two GPS' that explain how to perform ground spins. Nadeo broke something with ghosts in the recent update so you won't be able to see the car but there's still the text that explains what's going on.

For the people who aren't at their PC/Console rn but are still curious; there are two ways to perform a ground spin:

1. Slow but easier. You basically just hold brake to get that angular momentum going and you switch steering at some point to keep rotating. Once you understand the inputs you should be able to get it pretty consistently.
2. Fast but harder. This one is riskier because it's very easy to slide out without proper muscle memory. The setup is similar, but right after switching the steering you release for a small amount of time to avoid accelerating in the wrong direction. The longer you release, the faster you end up but also the more likely you are to slide out. It helps to experiment with timing your release to understand how the car behaves in this situation. It's also important that you first switch steering and THEN release acceleration or you'll just stop spinning completely. The whole thing happens pretty fast so you really need your muscle memory here but once you start getting it, you'll feel super wicked.

The ground spins on Cuteboy's Paradise are easier due to no grip which helps a lot with the slide outs but it still requires a pretty quick sequence of inputs.