Making private videos with your lover isn't unusual. Nor is it unusual for your phone to be the most convenient recording device around. Rumuki is a brilliant app that removes all kinds of potential concerns and lets you get down to having fun. First of all, you need to pair it with a copy of the app running on your partner's phone. Record away. When it's time to play it back, you both have to agree to it, and should one party delete their key, it's gone forever. So whether you're worried about being hacked or an ex posting your private bits online, you're covered.