What can you buy someone who has everything. The Essio Shower kit might be the answer!  Really easy to install and great for everyone.

There is an extendable arm that snaps onto the shower head that have a small pod attachment at the end. The pods are filled with essential oils that drips out slowly during your shower to deliver the most relaxing shower ever. The steam from your hot shower fills the whole bathroom with relaxing essential oils.

It is not oily and scents your shower into a mini personal spa.  The refill pods last anywhere from 3-5 showers from my experience.

http://essioshower.com/