After having like the @$^th dream with animal shapeshifting abilities, I get a trend that it's really difficult to maintain any shift (partial or complete) without constantly thinking about anatomy and physics.

Like wings or example, i can't make it work without being constantly aware of aerodynamics and weight ratios and wingspan, and then oh shit I forgot about rearranging the back muscle structure and now I'm falling.

Bleh.

Then if I were to think, "this is my world, these are my rules."

My dream mod goes 'Oh Yeah? Then input your world's fundamental laws of physics. No laws detected. Ah. Time to initiate total destruction of the dreamverse. Here's the endless vacuum of heat death. Enjoy.'

Damn. Lucid dreaming was way easier a few years ago.