My Cat Seems to Be "Flossing"

I have 2 cats. One is a 10 year old "tuxedo" black and white shorthair. In general he's well behaved except for his penchant for pulling threads out of certain pieces of furniture. He's been doing this for some time. I've observed him doing this carefully, it looks like he's "flossing" his teeth. He pulls the threads through his teeth.

Has anyone had experience with this? Might there be an alternative reason for this behavior? 

Boy, that's a new one on me!  I suppose it's possible that he did it once by accident and it felt good, so he keeps doing it.  He's doing it for a reason, that's almost certain.  Can you take a video of him doing this?  I would love to see him in action!  

It's good that you're watching him carefully when he does this.  Ingested strings have a very bad habit of getting entwined in the intestines, often needing surgery to extract.  Just a little warning....

BTW: Welcome to TCS.    

Often what you think a cat is doing is not what the cat it is actually doing. We do often amperphermorphise their behavoiur so it make sense to us.
He may be flossing or he may have found an amusing way of chewing/destroying stuff.
Every once in a while my girl will chew on a lamp shade or fight the blinds.
Probably not a good habit. Might have to get him to stop.
If I leave hair bands my girl eats them, then poops them out, then scrappes her but across the carpet to remove the hair band dangling out her butt. So @Margd is right not good for the cat.

Thanks for the reply. This isn't new or recent behavior, he's been doing it for some time. I just didn't realize what he was doing. At first I thought it was just a destructive habit, but it is restricted to only 1-2 places. Mainly my overstuffed chair that has a course weave fabric, it's 18 years old and has been through the wars, 3 cats and 2 puppies. Once I realized what he was doing I started to pay attention to the quality of his stools. I've not seen anything unusual. He's healthy, good appetite, no unusual health issues. At 10 years, that's a good thing.

I'll try to get some vid of him doing this, but that means I'll have to figure out how to use my IPhone for something other than phone calls.

Back story- He was born under my bed, our Collie brought his mother home, [Collies do stuff like that] she was a pregnant stray. The cat has never been outside overnight, he actually shows no desire to go out at all. If he should manage to get out he only goes as far as the first grass clump, and then sits at the back door. I keep flats of fresh cat grass going and that keeps him happy.

my cat quinn does this ! she'll find a string she likes and will hold one end down and pull it through her teeth.

I think it's part of pica. Magnus does this with carpet threads. Though, if the Yule tree is any example it's because he wants to pick the peices off and spit them on the floor.

We just cut the carpet threads off his tree as we see them to prevent the behaviour. He's comforted himself by ripping paper instead.