jig·gle 
(jĭgəl)
(jĭgəl)v. jig·gled, jig·gling, jig·gles
v.intr.
To move or rock lightly up and down or to and fro in an unsteady, jerky manner: The gelatin jiggled on the plate.
v.tr.
To cause to jiggle.
n.
A jiggling motion.
[ Frequentative of JIG1.]
jiggly adj.