every time collide play animation

i made a script but this make the collide animation play at first collide only (not every time when collide),
so how can i do that and here is my script :

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;

public class Collision : MonoBehaviour {

private Animator ani;
private AudioClip pontysound;

void Update ()
{
	ani = GetComponent<Animator> ();
}

void OnCollisionEnter2D(Collision2D collisionInfo)
{
	if (collisionInfo.gameObject.tag == "tamer")
    {
		
		GetComponent<AudioSource>().Play();
		ani.enabled = true;

    }


}

void OnCollisionExit2D(Collision2D collisionInfo)
{
	if (collisionInfo.gameObject.tag == "tamer")
	{
		
		ani.enabled = false;
		
	}

}

}

I do not now much about animation controllers, but maybe when the animation plays the animation doesnt get reset. So the animator is active but it isn’t playing the animation