"You have to do... what.... No!" the tiefling screamed when she realized what Mareth meant.  Her struggles slowed as soon as the succubus pressed her tail against the tiefling's sex, a soft moan escaping her lips as Mareth penetrated her.  As soon as she realized what happened, she blushed and glared at Mareth, though it was clear that, at least on some level, her body ached for the succubus's touch.