How to add a "fake" dampening after scrubbing through AnimationClip

Hi!

I'm scrubbing through a Animation with my MouseWheel and using this code attached to the animated Object:

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class ControlAnimation : MonoBehaviour
6. {
7.     public float speed = 0.01f;
8.  
9.     private Animator anim;
10.     private float animPos = 0;
11.  
12.     void Start()
13.     {
14.         anim = GetComponent<Animator>();
15.         anim.speed = 0;
16.     }
17.     void Update()
18.     {
19.         if (Input.mouseScrollDelta.y > 0 && animPos < 1)
20.         {      
21.             animPos = animPos + speed;
22.                }
23.         if (Input.mouseScrollDelta.y < 0 && animPos > 0)
24.         {
25.             animPos = animPos - speed;
26.                }
27.         anim.Play("MainAnimationClip", -1, animPos);
28.     }
29. }

This is working fine BUT:
The animation is stopping immediately when stop scrolling the mouse-wheel.

Now i'm trying to add some kind of dampening to the animation so it's "fading out" instead of stopping immediately. Guess using lerp would be the right tool - but no idea how to use it in this case

Any idea how to add such a dampening to this ?

Thanks in advance & stay healthy