There is acrually an old forum post with detailed instructions on doing just this in relation to having sat in the idle state too long.
And it had some tricks on how to blend from one pose to another which
@Nawrot really?
Essentially just take a pose snapshot, and toss the animation state machine into a state using said snapshot, then transition out to whatever else.
It should be something you can rig together in about 10 minutes.
Try it out