To control which items fire a popunder, you can add a "data-trigger-classes" to the invocation code.

For example, you would visit your site and find all the CSS classes for the items you would like to trigger a pop when clicked.
For Example:
On desktop your content photos uses the "i" CSS class & the text under the photo uses the CSS class "vttl". So you would add those classes to the data-trigger-classes like below. This would only fire a pop when you click on the content photo or content text.

It's important for your developers to go through the site & add as many non-navigation classes as possible. That way you can maximize the number of popunders while staying google compliant.
​
The Desktop code would look similar to this classes wise, but your team should review them.

<div id="adn-4783694" class="" style="">
    <script type="text/javascript" data-trigger-classes="i vttl">
        (function (parentNode) {
            var adnOpt = {"id": 4783694, "pid": 1333, "sid": 573, "type": 4, "width": 0, "height": 0};
            var adn = document.createElement("script");
            adn.type = "text/javascript";
            adn.async = true;
            adn.src = "//a.adnium.com/popunder?fpt=1&ctu=1&tu=1&r=" + Math.floor(Math.random() * 99999999) +
                "&id=" + adnOpt.id + "&pid=" + adnOpt.pid + "&sid=" + adnOpt.sid +
                "&tid=" + adnOpt.type + "&w=" + adnOpt.width + "&h=" + adnOpt.height;
            parentNode.appendChild(adn);
        })(document.getElementsByTagName("script")[document.getElementsByTagName("script").length - 1].parentNode);
    </script>
</div>