I came to this app few weeks ago. It seems good to have fun with friends. I tried on my roommate and at the first moment he believed that something is gonna happen! haha. Personally, I liked their idea for auto-start feature. It uses the back camera (I guess based on illumination) to make shaving sound.
It's free so I think it worth trying.
https://itunes.apple.com/us/app/ishaveit/id769408598?mt=8
It's free so I think it worth trying.
https://itunes.apple.com/us/app/ishaveit/id769408598?mt=8