Answer:
It's anything but amusing when this body part gets hit.
I can be moved. I can be rolled. But nothing will I hold. I'm red and I'm blue, and I can be other colors too. Having no head, though similar in shape. I have no eyes - yet move all over the place.
What has a bottom right at the top?
What flies forever, Rests never?
What force and strength cannot get through. I, with a gentle touch, can do. Many in the street would stand. Were I not a friend at hand.
People take me on walks and I run and have fun. What am I?