It took Susan a moment to adjust to the feeling of Terry inside her. It was a tight fit, and uncomfortable at first, causing a hiss to escape from her mouth at the new and strange feeling of being filled so completely.
Hearing him reciting arithmantic equations startled a laugh out of her, though, one that caused her body to move with the sound, and making her clench even more tightly around him. This time the hiss that escaped was a good one, and she felt the tightness start to coil again.
"Move," she instructed, hands tightening on his shoulders.