Topic: The Great Gatsby
Hello! Could you please tell me the meaning of "her body asserted itself with a restless movement of her knee" in the following passage of The Great Gatsby, chapter I?
Inside, the crimson room bloomed with light. Tom and Miss Baker sat at either end of the long couch and she read aloud to him from the “Saturday Evening Post’—the words, murmurous and uninflected, running together in a soothing tune. The lamp-light, bright on his boots and dull on the autumn-leaf yellow of her hair, glinted along the paper as she turned a page with a flutter of slender muscles in her arms.
When we came in she held us silent for a moment with a lifted hand.
“To be continued,” she said, tossing the magazine on the table, “in our very next issue.”
Her body asserted itself with a restless movement of her knee, and she stood up.
“Ten o'clock,” she remarked, apparently finding the time on the ceiling. “Time for this good girl to go to bed.”