Why You Should Really Care About Metadata by Sarah Jamie Lewis, is a good discussion and example of how dangerous metadat can be, especially around sexual activity.
Onion Dildonics Ecosystem
Onion Dildonics is a set of tools for more safely and privately using sex devices online via Tor.
From Sarah Jamie Lewis we have:
Android Onion Dildonics seeks to add a mobile Onion Dildonics client to the ecosystem. Built on top of Sarah’s Go Ricochet and my Ricochet Mobile Android OD is the first mobile ricochet app and the first mobile Onion Dildonics app.