Cass was torn. Torn between going on until Percy lost all control and came into his mouth and to stop in order to prolong this. It wasn't often that Percy seemed to be at the loss for words, and Cass guessed he wouldn't last much longer - at least it didn't seem so judging from Percy's breathing.
Letting his hand caress Percy's thigh, he finally moved back, taking Percy's thumb into his mouth for a moment before speaking. 'Lay back,' he said softly.