jQuery Toggle not working in Drupal
Most likely because the JS code you write in JSFiddle is automatically run when the document is ready; the same isn't true in a normal environment, you need to be explicit:

(function ($) {
  $(function() {
    $('div.applytoggle').click(function() {
      $('.applytoggle_title, .block-tellafriend').toggle();
    });
  });
})(jQuery);


But to be properly Drupal you should use behaviors:

(function ($) {
  Drupal.behaviors.myToggle = {
    attach: function(context, settings) {
      $('div.applytoggle', context).click(function() {
        $('.applytoggle_title, .block-tellafriend').toggle();
      });
    }
  };
})(jQuery);