RotateConstant

using UnityEngine;
using System.Collections;

public class RotateConstant : MonoBehaviour {

    private bool pointerEnter;

    // Update is called once per frame
    void Update () {
        if (pointerEnter) {
            transform.Rotate(0, 0, 20 * Time.deltaTime); //rotates 20 degrees per second around z axis
        }
    }

    public void PointerEnter() {
        pointerEnter = true;
    }
    public void PointerExit() {
        pointerEnter = false;
    }
}