The evolution of Terrance the Dog's nap, documented in photograph form.

The insistent butt-touch:

WHO DISTURBS MY SLUMBER?!?!?

The... wait, dude, what are you doing?

WHO DISTURBS MY SLUMBER?!?!?

Ok though there's seriously no way this is comfortable.

WHO DISTURBS MY SLUMBER?!?!?

The pillow mount:

WHO DISTURBS MY SLUMBER?!?!?

The headrest:

WHO DISTURBS MY SLUMBER?!?!?

Dogs are weird.

ETA: Now he's snoring.