How to call a while loop?

Hello i am making a game like curve Fever.
I want that the player placeses a block every 1 second behind him.
The problem is that i don't know how to call the while loop i made this script:

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class Draw : MonoBehaviour {
5.  
6.     public GameObject prefab;
7.    
8.    
9.     void Start ()
10.     {
11.         MyLoop2 ();
12.     }
13.  
14.     IEnumerator MyLoop2 () {
15.         while (true) {
16.             Debug.Log ("I've washed a cup!");
17.             yield return new WaitForSeconds (1);
18.         }
19.     }
20. }

Why doesn't this work???

 

Code (csharp):

1.  
2. StartCoroutine(MyLoop2());
3.  

 

Thank you i am just stupid......