I keep mine in my console mostly or one of the cup holders. But often, I just keep it between my legs. Also, I have put it on the dashboard behind the steering wheel on occasion, or in my visor. Lots of places to stow it. Just not my pocket....too hard to retrieve while driving.
I keep one between my legs too and if I have a skirt on I just hike it up. That might not be a good solution, though, if you have a front seat passenger that is not a familiar mate or friend.
I like Big Hitter's solution a lot. Problem with DH's car is that usually the only two cup holder are in use when we are both in the car. I usually have a Grand and a Mini or a Woodvil, two Reos in the car with me. The only place for a second one, in his car is the console but when I turn corners I have to hold it to keep it from falling over. My car has plenty of cup holders and places but I'm sure many don't. Both cars are automatic so I'm not moving my legs a lot. So, sometimes I have both Reos between my legs. In heavy traffic, when, switching between brake and gas pedal I don't like to have two in my lap because I don't want them to abrade and mar each other; just like what would happen with shifting frequently.
One of those plastic cheap door cup hangers might work; the kind that slips down into the window grove. And then fashion something like what BH is suggesting.
DH's car's "ash tray", or what used to be used as ash trays, more frequently used for change now days, is too shallow for a Reo. Occasionally I'll make a quick acceleration and propped up Reo will go flying, even off the center console. I hate when that happens. Sometimes, when I'm driving his car without a passenger. I'll prop extra Reo up against passenger seat back but a quick stop causes it to tump over. I hate that too.
Alice