Donkey Kong keg eject

Im trying to do the same as donkey kong game. At the moment, my object enter on the keg, but i cannot aplly force to "eject" the object from keg. What im doing wrong?

public class Keg : MonoBehaviour

{

 public float zPos;

 public Rigidbody2D rb;

 public bool foxIn;

 public FoxOnKeg foxOnKegScript;

 private float force = 50f;

 void Start()
 {
     foxIn = false;
     rb = GetComponent<Rigidbody2D>();
     foxOnKegScript = GameObject.Find("Raposa").GetComponent<FoxOnKeg>();
 }

 
 public void FixedUpdate()
 {
     

     if (foxIn)
     {
         zPos--;
     }
 }

 public void OnCollisionStay2D(Collision2D other)
 {
     var keyboard = Keyboard.current;

     if (other.gameObject.CompareTag("Player"))
     {
         foxIn = true;
         other.transform.SetParent(transform);
         other.gameObject.transform.position = new Vector2(transform.position.x, transform.position.y);
         transform.eulerAngles = Vector3.forward * zPos;

         if (keyboard.bKey.wasPressedThisFrame && foxIn == true)
         {
             other.rigidbody.velocity = transform.up * force;
             //rb.velocity = transform.up * force;
         }
     }
 }

 public void OnCollisionExit2D(Collision2D other)
 {
     if (other.gameObject.CompareTag("Player"))
     {
         foxIn = false;
         zPos = 0f;
         other.transform.SetParent(null);
     }
 }

}