Stay classy and use this Pocket Watch for Pebble Time (works great with a moustache and a suit!)
This model can bend to fit in a pocket.
I used intentional3D's model as a starting point (you can find it at http://www.cgtrader.com/3d-print-models/hobby-diy/other/pocket-watch-and-chain)
The model is made of two parts:
When the two parts are printed simply plug the flexible part into the rigid one with the build-in indentation.