Re: You're holding it wrong!
NOT the BACK pocket - I have actually seen people do this with phones. Cracked screens and butt-dialing frequently occur, no doubt.
iPhone in back pocket on a chopper, large 2 cylinder engine, no shocks, seat bolted to the frame. That'd do it, yeah.
Use FRONT pocket, or some kind of handlebar or gas tank shock mount for the phone.
/me thinks ape-hangers with a phone mount. heh.
(alternate concept, phone inside helmet)