twittem/wp-bootstrap-navwalker — pull request #43 by yazdi (2013-10-16 18:17:33+00:00)
Title: add Description menu after title

Add Description in <span> after title , between link
<a href="..."> title <span>description</span></a>

Note: display at span must be block (display:block;)
#your_container_id span { display:block; }