Tom closed his eyes now, feeling another orgasm reach him.
“I’m cuming, Kate! I’m cuming!”
Kate put her hands on his shoulders and used them to move up and down even faster. Her vision blurred, she felt the familiar tickling in her spine and seconds later the orgasm hit her. She screamed and started shaking, driving Tom’s dick deeper than ever. She dug her nails in his shoulders and screamed his name again and again.
When he felt his sister’s pussy contract around his dick, as if wanting to milk it, he came again, this time deep in his sister. He held on her calves and raised himself a bit out of his chair, making sure he was as deep as he could get as he ejected his load. He moaned his sister’s name again and again, as he felt both their cum juices mixing. He kissed his sister’s chest, right between her breasts and she moaned a final time.
They stayed like this, her on top of him, him still in her, for a while, enjoying the afterglow. An hour later, Tom was back at his paper, almost done. Kate was by his side, caressing his hair and still enjoying his body. They were already thinking of new ways to experiment with each other. They both had a few positions they wanted to try… And they both wanted to moan each other’s names again. And again.