On PC, you did not say which version,, I used the "Q" key (defualt I think) that transforms to dragon and back to human and vice-versa.
You can also drag that dragon stone into one of your quick slots at the bottom of the screen just like a skill.
One thing I did not like about this game is it did not have enough quick slots, but that is way off subject. silly


Windows 7 pro 64 bit
EVGA X58 motherboard
6GB of OCZ DDR3 memory
watercoooled i7 920 @ 3.8GHz (4+4 cores)
EVGA (Nvidia) GTX 275 graphics
Creative X-fi elite pro sound card.