As explained in this post, about the Physics of Spanking, if you want to be quiet but stingy you’ll want to choose an item with a thin cross section. The sound of a smack is proportional to the impact surface area, so paddles and hairbrushes tend to be the noisiest.

So the best items for quieter spankings are thin rods (especially those anchored at one end), such as canes, switches or spanking crops. A thin wooden ruler or a paint-stirrer would be slightly noisier, but still much quieter than an open palm.

Make experimenting part of the game. Download a decibel meter to your phone and start collecting data, you might find the loudest noises aren’t actually the spanks, but the moans they inspire…