An MPS spinnaker is used on a broad reach (when the wind blows from the side of the boat) or a run (when the wind comes from behind) in light winds. A pole is not required to hold it in place.
It has a tackline that holds it to the bow of the boat, and a sheet (rope) that is used to control it.
When it is time to bring the sail down, it has a sock that wraps down over it like a pillowcase.
Link to You Tube showing how the MPS is raised and dropped
The links below are worth a read.