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")
            StartCoroutine(SetActiveAfterTime(1f, collision.gameObject));

IEnumerator SetActiveAfterTime(float time,GameObject go) {
        yield return new WaitForSeconds(time);

Try changing the Sleep Mode on your RigidBody2D to Never Sleep, and see if that helps.