A little snippet for WordPress. Paste this in the header.php
<? if (!is_home()) { ?>
<script>
jQuery(document).ready(function() {
if( window.innerWidth < 700 ) {
$('html,body').animate({scrollTop: $("#mobile_menu_end").offset().top},'slow');
}
});
</script>
<? } ?>
Then place this IDed div below your menu.
<div id="mobile_menu_end"></div>