Ockham's Jiggles script can work for this sort of thing.  It's designed for use with motion morphs, but I've gotten it to work nicely with body handles.  I tend to set the "twang" too high, though.

I think there's a "jell-o magnets" script somewhere which may try to achieve similar effects in a different manner....

Edit:  Oops.  Scooped by Ockham himself.... 

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Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.