How to make my rotating sphere sticky?

Hi, I have a cube and a sphere both made of Rubber and both have a rigidbody.

Here are the cube's parameters that I've changed from default:

• Freeze position on Z

• Freeze Rotation on every axis

Here are the sphere's parameters that I've changed from default :

• Does not use gravity

• Is kinematic

I place my cube centered above my sphere and I let the cube fall on the sphere. If I apply no rotation, the cube will stay balanced on the sphere and will not move. But what I want to do for my game is I want the sphere to rotate on itself so that the cube can't stand on it.

To do this, I uses a script that changes the rotation of the sphere on each frame :

 public int rotationAnglePerSecond = -30;
     
 // Update is called once per frame
 void Update () {
     transform.Rotate(0, 0, Time.deltaTime*rotationAnglePerSecond);
 }

With this script, you'll find out that the sphere turns slowly and pushes the cube next to it like it should. But my problem comes when I increase the rotation speed. Instead of making the cube fall more quickly, the cube just slips on the sphere and takes a long time before falling off (try with -180 instead of -30).

I don't understand why my rotating sphere affects less the cube when it's rotation speed is increased. They are both made of rubber, shouldn't they stick together instead of slipping?