He liked to pleasure Arethusa, in the middle of punishment. She didn’t always want to admit how turned on she was by the whole situation: his commands, his lecture, the kiss she was required to bestow on the cane, and then the stripes of fire.
But her Master always found her wet, in the middle of any caning. Sometimes that discovery meant the caning was over. There were other priorities, that had just made themselves more urgent.
A slavegirl needs to be pleasured. And, well, being her Master was all duty.