The more Katie wriggled, the more sensitive her body became.  She made eye contact with Chloris and nodded back to her.  She would continue to struggle until they were free, if it ever came to that.  But the sensations were a lot stronger now and her breathing became harder.  One might assume she was breathing heavily and let out muffled groans because she was working so hard, but it was also due to the heat rising in her body.  A light layer of sweat moistened her body and she continued.  Her most sensitive areas were rubbing against the Doctor and soon Katie was even getting distracted by the feelings that were rising from their efforts.