Thumb the spool as you release line, to stay in contact with the rig and sense bites. A final note on sabiki safety involves protecting the bait rod itself. This will prevent kids, novices and probably yourself from reeling the swivel through the tip. A black bead is preferable if mackerel are in the area. Red is the universal color of distress in the ocean, resembling the flaring gills of potential forage, and may attract strikes from fish that can cut you off hook, line and sinker, so to speak.
Some anglers also coat sinkers with a layer of black paint to further deter unwanted bites.
If you choose to connect the sabiki rig to your line with a snap swivel, it, too, should be small and black.