The sensitive area where a slave's ass meets his thighs contains many nerve endings. I've picked a particular wooden hair brush with stiff natural bristles to work over this particular spot. Alternating between fast smacks and running the bristles over his backside, I can hear his breathing change. As My slave starts to shake I can sense his adrenaline and endorphins kicking in. Though I definitely want to leave some of his backside left to indulge in sadistic intentions later.