it's not, not possible, as you can use the morphs to do this! but to make it look right, you are gonna have to do it a few times to get it "subtle", to begin with it will look excagerated, but with fine tuning, can be made to look right.

for male anotomy (men sway, not jiggle!! just checked!) this can be achieved by using either the segments of the part, with the side to side morphs, or using the posing morphs usually used to "flop" when lying down, on one side, so you could use the lie to the right/left dials.but again subtlty is key, otherwise you end up with a "snake charmer effect"

but if you wanted walking aswell as "jiggle", you need hip rotation, and weight displacement, and compensated body shift, compensating for weight displacement, then variation in walk, if you think about someone walking up to a pedestrian crossing, and the actions they do approaching,arriving at, and leaving said pedestrian crossing, so they might avoid/monuvere around someone as they arrive at the crossing, then they might be the one that presses the button(for the green man) then stand there maybe impatiently looking around for when it's safe to cross, then cross, lots of movement going on there.weight shifting to change direction to  avoid collision, weight displacement and balance to lean over to press button and so on... 

or maybe someone pacing up and down, talking to themselves, maybe reciting a proposal or something, with the walking(feet motion) there is also gonna be hand gesturing, as they go over what they are gonna say, speech and facial movement and emphasising hand gesture, to make a point, all is possible with poser but it takes time to create, you have to accept that it takes time and settle down to take your time, so as to make an anim worth looking at.

there are lots of free mo-cap files (motion capture) out there, that you can use to assist you. there is so much more that you can do with posers animation palette than just make a 30 frame walk cycle loop with wobbly boobs.you just have to put the work in.

"ok scene one ,take two, roll 'em................no ! ,no! vicky baby! i said clothes on for this scene!!!CLOTHES ON!!!...cut!..CUT!!!"