Phone shoes

Another weird and wonderful invention here - a mobile phone that is housed inside your shoe. Genius! Saving space in your pocket the shoe phone would just suddenly start ringing so you undo the laces, hop around to keep your sock off the floor, and then chat away - what could be simpler. There's the potential for a good joke in here about using your tongue to talk into the tongue, but we can't find it. Anyone got a good suggestion?