I want to slide toggle the second level ul when I mouse over the relevant first level li.

Currently the script displays all secondary ul on a mouseover.

<div id="subNav">
<ul>
   <li>One</li>
       <ul>
           <li>SubOne</li>
       </ul>
   </li>
   <li>Two</li>
   <li>
       <ul>
           <li>SubTwo</li>
       </ul>
   </li>
</ul>
</div>

And here is my jQuery

$("#sideNav ul li").hover(
        function(){
            $('#sideNav ul li ul').slideDown();
        },
        function(){
            $('#sideNav ul li ul').slideUp();
        }
    );