Yes!! Izzy does it all the time especially to pillows, she has her own old ratty pillow case that she sucks on when shes angry. She bunches it up then kneeds it and sucks on it till she falls asleep. She does it with sheets and blankets too.
The "mix" thing is what kittens and pups do on the mom's teats to help "let down" milk. This is all rather like thumb sucking in kids, but there is no peer pressure from other kids to stop