Id have to go with Loviatar.....Mistress of Pain..Maiden of Hurt.....

hell..shes always been my fav S&M goddess from D&D.....

(gawd I am such a geek for even having a fav goddes from D&D )

course you could break out the Book of Erotic fantasy and use some of the ideas from that book....

The book is a locally done project(seattle area) that brings sexual eroticism into the D&D game setting......

(Gawd I am even a bigger geek for knowing this )

http://www.bookoferoticfantasy.com/