Sits in a cup holder, requires two loops of elastic (or hair ties) which allow the holder to clamp the phone in place. Due to stretching it kind of partially auto-centers itself (if the elastic had more tension it would be more likely to, at the cost of maximum stretch). The arms have a chamfer that extends inwards to wrap around the edges of the device it's holding.

The elastication makes it easy to slot in one-handed, and secure whilst it is in. The cable routing supports a right-angle charging cable, but only in one direction. STEP file included if you want to modify it.

Probably best if it is weighted; I paused it and poured sand in it before sealing it with hot glue so it wouldn't get blown everywhere.

Works for a Nissan NV200, and probably most cup holders; STEP file is included for easy modification.