Crossword puzzle clue "couldn't sit still say"

Couldn't sit still, say

Couldn't say "say," say

Couldn't remain still

Say "You mutts couldn't catch a dead grouse," say?

Say "I couldn't solve this clue," say

Grammy nominated singer with the 2015 album "Sometimes I Sit and Think, and Sometimes I Just Sit"

Where a cat might sit when you sit down

Least likely to sit still