Although idlers have enjoyed lying supine on couches for centuries, staring at the ceiling and thinking deep thoughts, that activity has been (almost) spoiled by the invention of the TV remote. Why? Not so much because channel-surfing is bad for you (although channel-pottering is better, of course), but because one would not want to be taken for a couch potato, whose unhappy existence is devoted to distraction-without-end. See: SLACKER, SLUGGARD.

an idler who spends much time on a couch (usually watching television)

a person who lies all day, on their couch in front of their television

What Mom finds under the sofa cushions after the kids eat dinner.

a cathode-ray tuber