If you insist on snapping nudies...
Why not use an actual photo camera instead of a phone? You'll get better quality images, the images will be stored completely offline and so there's no risk of exposure unless you want to and best of all: most have an auto timer so you could even be in the picture together!
Seriously though, I don't understand why anyone would want to snap pictures like this. That is.. I do understand but fact of the matter is that you'll have a much more enjoyable time together if you keep those moments for what they are: private and therefor special.