Why does my cat poop on my couch?

She has been pooping on the couch for about 6 months now. She poops in between the cushions and on blankets. She even pooped on my brothers jacket twice. Shes 7 and a half years old and is a tabby cat. She still poops in her litter box most of the time. She usually starts to meow before she does it as well. Help!