Any suggestions on what can deter a cat from tearing up furniture...???

2 weeks ago I bought a new couch and loveseat when my fiance and I bought a new house. They both sit up off the floor on legs just enough that the cats can get under them. Of course there is the black lining on the bottom that covers what would be the opening there. My cats (well maybe only one of them, I cannot catch them in the act) have decided that it would be neat if they could make it a new hiding place. They have torn a hole in the lining just big enough to be able to climb inside and lay in it and start to tear up and play in all of the stuffing and the springs. They also started to claw the outside arms. These cats have not really done anything like this before. They have scratching pads and posts and toys that have usually kept them occupied. They still use all that stuff too, just added the furniture. Any suggestions??? I have heard feliway is good to keep cats from clawing things, but this is supposedly when it is because of stress, it looks like mine are just having fun :(