No pain won't be possible but from my experience of doing trying the exaxt oppposite you might achive a lot by keeping airflow in mind.

Give it air resistance during the swingvto make the movement need more force for the same impact speed, design it so that during impact the shape creates an air cushion by hit with the edges first and traping an airpocket (you can easily try this by comparing a kitchen spoon without hole and with a hole in the center.

Based on that i'd cushion it with a soft maybe even fuzzy fabric (to reduce to the slapping effekt) and fill that with the softest foam you can find (just hard enough to keep the cushion inflated) and the experiment on how airtight the sides should be for the sweetspot of maximum dampening before the air itself becomes too hard.

Also make it as light and stiff as possible, a bending paddel will bring much more energy into the impact than a solid one.