Definition of "wriggle"

Both he and successors would often wriggle in their seats, as long as the cushion lasted.

1724, Jonathan Swift, “Drapier's Letters”, in 5

In this category the Wriggling Orator claims our attention. This St. Vitus-like speaker does not stand firmly in his boots, but his feet wriggle from heel to toe and over one another; his knees are not braced to hold up his body, but they wriggle outwards, inwards, backwards, forwards; his sides are not erect to sustain his chest, but they bend and wriggle, first one way then another; his shoulders are not squared to the spectator's eye, but they wriggle up, down, out, in; his arms are not expanded in their movements, but they wriggle about and seem to crawl over his body. His head wriggles on the wriggling neck,—his tongue wriggles in his mouth,—the words wriggle out,—and he wriggles all over, and all together.

1886, Alexander Melville Bell, “An Alphabet of Orators”, in Essays and Postscripts on Elocution, page 171

I tried to ease my grip, but my hands were sweating so profusely that the lizards began to wriggle out of them.

1972, Carlos Castañeda, The teachings of Don Juan: a Yaqui way of knowledge‎, page 78