Weed that is searched for in a desperate attempt to get high, found in places that weed is frequented. These places include carpets, dressers, and couches. Couchweed may contain various kinds of ( probably old) weed, pocket lint, pizza crust, maybe toenail clippings.
person1: yo, dont forget you owe me weed
person2: damn, im all out, let me look in my couch
person1: hell no son, i dont want your couchweed
person2:shit, ill just pick up a dub