This question has been answered by multiple community members. See the first response.

$('.i-btn-more').click(function(){
var el = $(this).parent();
el.find('.i-more').toggleClass('shown').toggleClass('hidden');
});
$('.i-btn-more').on('click', function(){
$(this).siblings('.i-more').toggleClass('shown hidden');
});Or slightly shorter:
$('.i-btn-more').on('click', function () {
$(this).parents('.i-holder').find('.i-more').toggleClass('shown hidden');
});
<a href="javascript();" class="less">Show less</a>

$('.i-btn-more, .i-btn-less').on('click', function (e) {
e.preventDefault();
$(this).parents('.i-holder').find('.i-more').toggleClass('shown hidden');
});
;(function() {
'use strict';
$(function() {
var $containers = $('.i-holder');
$containers.each(function() {
var $container = $(this),
$more = $container.find('.i-more'),
$handlers = $container.find('.i-btn-more, .i-btn-less');
$handlers.on('click', function() {
$more.toggleClass('shown hidden');
e.preventDefault();
});
});
});
})(jQuery);