Mostly the left side of the couch. With the mouse on a cushion to my left (because I use the mouse left-handed). And a book under the laptop to keep it from burning my legs.
I'm usually on my desktop, which is on my desk in my office. I work online, so I need a proper desk and chair so I can work 7 or 8 hours comfortably.
I also have a laptop that I mainly use for playing YouTube yoga videos. Then I'm on my yoga mat, in the main living area, contorting myself into all kinds of weird positions.