I'm sure this is really simple but...

I'm converting a superfish responsive menu for a WordPress template and have managed to implement a version based on this jsfiddle. To polish it off I want to add a simple slideDown/slideUp effect for when you click on an item and its children open up in (the mobile version of the menu).

<http://jsfiddle.net/badlydrawnben/c5MJy/> - slide the bottom bar across so you're seeing the <480px version

The code I have is 

```
$('li.has-children').click(

    function () {
        $(this).toggleClass("xpopdrop").siblings().removeClass('xpopdrop');
            });

```

but however I try to add a slideDown function in there too, I can't get it to work.

Any ideas where I'm going wrong?

Thanks,
Ben