Potatoes on the lounge chair; Sofa potatoes; loafer

Example selection

1.

If I wanted to I could just be a couch potato for days on end.

I can be a slacker all day if I want.

2.

His mother always warned him he'd turn into a couch potato if he watched too muchTV.

His mother always warned him that watching too much TV would turn him into a couch potato.