n Hence, something carried in the mouth to distend the cheeks.
n In elections, a vote given to one candidate only, when two or more are to be elected, thus giving him or her the advantage over the others; a person who gives his or her vote thus is said to plump, or to plump his or her vote.
n (internet|slang) An obesewoman, especially in pornography. [http://groups.google.co.uk/groups/search?q=%22plumpers%22+bbw&btnG=Search&sitesearch=groups.google.com]