A chemise is usually a little more loose fitting but it is a popular search term so I would use it
Here's a good link for lingerie terms:
http://www.glossary-of-terms.net/glossary-of-sexy-lingerie-terms.html
Also do a mpire search for a few keywords and see what you get.
I'm pretty sure people won;t be searching for snakeskin lingerie so you could better use the title space. Make sure you get in Lingerie, Sexy, Chemise, Long Gown and the size of course.
hope this helps