OnCollisionStay2D deactivates after a short amount of time

I'm pretty new to Unity and I'm currently experimenting around.

Situation: I have a sphere which is the Player. The sphere is standing on a plane. By pressing "s" I want to deactivate the plane, so that the player falls through, then reactivate it.

While moving this works perfectly fine.

But after not moving for maybe half a second, pressing "s" does not do anything.

 void OnCollisionStay2D(Collision2D collision)
     {
         if (Input.GetKeyDown("s") && collision.gameObject.tag == "plane")
         {
             collision.gameObject.SetActive(false);
             StartCoroutine(SetActiveAfterTime(1f, collision.gameObject));
         }
         
     }
 
 IEnumerator SetActiveAfterTime(float time,GameObject go) {
         yield return new WaitForSeconds(time);
         go.SetActive(true);
     }