The spinnaker is forward, which I guess you call “under” the jib sheets. Forward is towards the bow, or front of the boat. The halyard, spin sheet and guy, and the sail all stay forward of the jib sheets. The confusing part is that it is not in relation to your body, but in relation to the boat.
I had a crew for a while who was an All American at the Naval Academy. She would loop the jib sheets behind her head to douse the chute. This meant the chute always got stuffed without the jib sheets tangled.