Originally Posted by
c_m_shooter
You cog and lockring are not tight enough.
If you don't have a chain whip to properly tighten the sprocket, try the rotafix method:
https://en.wikipedia.org/wiki/Rotafix
If you do one good skid the way it is now, you will strip the threads off the lockring.
More likely, strip the lockring threads on the hub, which, unfortunately, is even more expensive to fix. It's also possible that the OP is experiencing this issue because the hub is already damaged. Remove the lockring and sprocket and carefully examine the threads.
IMO, skid stops should not be your default method of stopping your bike in the first place.