In my very humble opinion, a ball gag might serve as a good logo. It's not as vulgar as it sounds! It could symbolize Ally and Lisa's metaphorical gag which prevents them from expressing their true desires to the world... or whatever...
Just a word of advice from halfway around the world, but in my neck of the woods, Sunstone is a religious organization with a lot of creative ties. A Google search may provide more guidance so as to avoid confusion.
Of course, I know you love confusion, and even I have to giggle a bit at the idea of some not-terribly-prudish person coming across your art innocently. Just a thought. <[link]>
I like it. It deals with the bondage, but at the same time could be symbolic of the relationship in general, how Ally and Lisa always seem like they're so close to breaking the relationship when it gets really serious, but choose not to.
i prefer Shiniez Sunstone sounds lamely generic and uninteresting to an outsider, and at the same time too specific for an insider - when you get to that part in the story where the safeword is explained, the reader may have a feeling of having discovered the secret behind the whole comic (as stated on the label) - and that it's just gonna be downhill from here.
I guess i'm saying, a name like that takes the feeling of open-ended expectation outof a comic. Sunstone... limits things.