I have one and it did take a lot of kegel exercises to be able to keep it in and keep a good, tight hold on it. I have this harness and really like it -
http://www.holisticwisdom.com/stormy...er-harness.htm - it's comfortable and I can use it for several different toys - good luck to your wife and I'd tell her to maybe get a good kegel exerciser like
http://www.holisticwisdom.com/smartb...un-factory.htm - that's what I used and it's really helped - especially after having kids!