How do I connect a vibration sensor/switch to a breadboard?
It appears from this information source:
http://www.electrodragon.com/product/vibration-switch-sensor-sw-18020p/
that the sensor is an electrical contact on the firmer side surrounded by a very sensitive spring within the enclosure. The coil spring is by design made of a smaller diameter wire to provide sensitivity to movement. Rather than manufacture a translation to a heavier piece of material, the thinner lead is brought out of the enclosure.

I suspect that it will not work on your breadboard, due to the flimsy end being too small to make solid contact within the breadboard. You could resolve that aspect by soldering on a heavier segment.

Because it is designed as a simple switch, there is no plus or minus.