Make like Jell-O

• Slightly bounce
• Shake, like a faulty toilet handle
• Do what Jell-O does
• Move like gelatin

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1836, from jig (q.v.) + -le , frequentative suffix. Related: Jiggled ; jiggling . As a noun, from 1840.

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Jiggle \Jig"gle\, v. i. [Freq. of jig.] To wriggle or frisk about; to move awkwardly; to shake up and down.

Wikipedia Word definitions in Wikipedia