Some years ago I came across what was and I think still is considered the ultimate vibrating sex toy for women: The Sybian.
This is a Sybian. It’s designed to be sat upon (with your choice of attachment for penetration, or not). And it has a remote control unit for vibration speed/power.
A woman can use the Sybian on her own, or with the soft cover without the penetration insert (bottom centre in the photo) then it is possible for a couple to have sex doggy style while she receives strong clitoral stimulation.
I mentioned the Sybian to a client the other day (hi Rachael!) and she came across a relatively new site through Google of a Sydney based company that offers Sybian parties and hire.
You can see their site here:
Sweet Sybian Sydney run parties just for women and also for couples to try out a Sybian.