AtD translation: Now and then he creaked around in the saddle

[Mike Jing]

P214.19-24   Each explosion was like the text of another sermon, preached
in the voice of the thunder by some faceless but unrelenting desert
prophesier who was coming more and more to ride herd on his thoughts. Now
and then he creaked around in the saddle, as if seeking agreement or
clarification from Webb’s blank eyes or the rictus of what would soon be a
skull’s mouth.

What does "creaked around" mean here? Is it just moving around with a
creaking noise, or something else entirely?