I've noticed in a couple reviews when discussing very petite or small women, that they are described as being spinners.

Now my mind can be quite creative, but I'd like the more mundane explanation for what this means.

My ideas for your amusement:

1) That swing seat that you can wind up, set her down onto you, and let go, and she spins you off.

2) Someone you can manually spin around on you.

3) (More Mundane) Someone that is so small, you can maneuver into different positions without breaking penetration because you can hold her up with your arms while you reposition.