But now the arm flexed involuntarily, tickling me on the back.

The arm flexed and hurled him against the unmaimed son.

He moved in the seat, flexed his injured arm.

Powerful arms flexed, and the iron shaft slid forward.

Her arm flexed, long claws tickled down my face.

Backs bent, the machine's arm flexed, the leader felt himself pulled up on to his toes.

His arms flexed, pulling her up to look at him.

His arms and legs flex, adjusting his balance in order to maintain the necessary course.

Now and then his hands contracted, arms and legs flexing involuntarily.

The major's massive arms and shoulders flexed against his chains.