2 adjectives to describe squirm

We stood for some little time watching the natives going to and fro, passing one another with perfect ease by means of a dexterous squirm, and carrying loads on their backs, or live fowls under their arms, with the utmost unconcern.

The guard winds his horn, and after a preliminary squirm of the plump tyres on the soft road, the vehicle and its company goes tumbling down the road as if it were descending into a pit.

2 adjectives to describe  squirm