Edit in JSFiddle

$(function () {
    var num = 0;
    var appendit = function(n) {
		var div = document.createElement("div");
		var txt = document.createTextNode(n + "回目のループ");
		div.appendChild(txt);
		var wrapper = document.getElementById("wrapper");
		wrapper.appendChild(div);
    }
    var appendit_after = _.after(3, appendit);


    $(".trigger").click(function(){
        for(var i = 0; i < 4; i++) {
          num++;
          appendit_after(num);
        }
    });
    
});

<p>_.after Practice</p>
<div id="wrapper">
    <a href="#" class="trigger" >クリックして発動</a>
</div>

p, div {
    margin: 20px 20px 0px;
    clear:both;
}

div.trigger2{
    color:red;
}