Something neither Ty nor Eileen really thought about in their aroused post-coital haze was how they'd just fucked raw, again. Unbeknownst to the two of them, transforming like they had had caused the innumerable sperm in Eileen's balls to bind together into an egg, and Ty's freshly-released sperm scented it and raced through her fertile pussy towards it.
Once they reached the ovum they eagerly chewed away at its walls, and the egg soon capitulated to the fastest one. While Eileen might be older than most women, she was still nowhere near menopause, and Ty's youthful, virile seed had an infectious, primal desire to conceive that made her body capitulate to the need. The combined sperm and egg soon began to form a xygote and divide rapidly, before slowly moving down into Eileen's womb and implanting in its wall. A decade and a half on from her first pregnancy, she would be bearing another child.
Naturally Ty and Eileen were blissfully ignorant of this as it all took place. Ty withdrew from Eileen, the two of them staring enraptured as his pale shaft was extracted from her dark body and thick white seed dripped from her lower lips. He kissed up her stomach and chest, making her giggle as he reached her pretty face and they kissed passionately, cuddling on the floor of her living room in a messy, happy pile.
At last Eileen stood him up and said, "OK, now you really should go, Ty. Thanks for all this, it was so fun!"
"I'm glad you liked it," the teen grinned. "Maybe we can do it another day?"
"I don't see why not," Eileen agreed, and she kissed him again before heading off upstairs and hastily finding a dressing gown to put on before she saw him off.
Ty sneaked back to his house and into his bedroom, and kinda lay in bed in wonderous disbelief. He'd really gotten to try out his powers on Mrs Paulson- or Eileen, he realised- and turned her into a man, himself into a young woman and fucked him, and then changed them both back and they'd fucked again. All of that wasn't possible, or at least was stuff he really shouldn't have done, but they'd done it anyway and they loved it.
He wondered what to try using his powers for now...