Ok, so I'm writing a short story about a guy getting laid with various girls. He's a bad seedy guy so he wants to video him screwing them, so what would be the best way of discreetly filming the bedroom action at the best quality and with a surefire way he'll never get spotted? Phones are a good handy option but a bit bulky and conspicuous, is there something the character can buy to help disguise it? A way of getting whatever it is to switch on whenever there's movement, long battery, etc.

All fiction so no outside eyes need to get upset..

EDIT: Actually fuck it, anyone got some good tips on how to get away with this shit and make the best quality recording? Some kind of expert guide would be great