Swoon Shimmy

Ao I received the swoon shimmy kit as a frewbie with an order yesterday. I am just about to jump in the shower and thought 'I'll take it with me and have a play'
So I've just got it out screwed the battery cover nice and tight and found that if it is screwed tight, it doesn't work :-/ it makes a bizarre squealy noise but no vibrations. However, if I loosen the battery cover a little it springs into life.
Surely if it is meant to be waterproof it would need to be screwed nice and tight?
Do we think it could be a faulty one?
I'm taking it in the shower anyway to see if it does work in water even if it isn't screwed tightly, and if not it looks like this may be my first return!
Will update shortly! (I have my g-wizz as back up just incase the swoon won't work, so at least I'll still have some fun!! )
:-)

Well it seems to work fine :-)