children
The siblings method selects the sibling elements of each element in the collection and returns a new collection containing the sibling elements.
// Select the sibling elements of the elements
siblings: function() {
  var siblings = [];
  this.elements.forEach(function(element) {
    siblings = siblings.concat([].slice.call(element.parentNode.children).filter(function(child) {
      return child !== element;
    }));
  });
  return $(siblings);
}