A couch potato is basically someone who is lazy and likes to lay around on the couch a lot and doesn't get too much exercise.
Being a couch potato is just basically someone who watches too much television and never or hardly ever leaves the couch nor gets away from the television too often.
The idiom couch potato was created for someone watching too much television because in some western countries, a person usually sits on the couch when watching television although some people will be sitting in a recliner when watching television.
So those people could be referred to as a recliner potato although I've never heard someone say someone was a recliner potato but they could be.