Making a ball rollwith oblong object

So, i am trying to make a katamari clone but i am having difficulties imagining on how i should imitate the ball rolling with oblong objects. as show in the link below when the speedrunner picks up oblong objects. https://youtu.be/PH7Tr6eF8s8?t=30m36s

Since right now it is just sliding around like this. https://gfycat.com/PleasedSplendidAuk

I have no scripts made for this and my ball is just being applied rigidbody forces.