The oral sex felt great, but Mark wasn't satisfied. John was just too sexy to resist and he had to have more. He pulled John up off his knees with his powerful arms and turned him around, quickly ramming his large hard cock into John's cunt.
"Not in the pussy! You can't fuck me there!" hissed John.
John had actually been enjoying himself as he sucked Mark's cock. The feeling of a hard rod in his mouth aroused him for some reason. He wondered if the change in his body had also affected his mind a little. But John didn't really care. He was getting incredibly aroused as he pleasured Mark and it felt so good. His pussy began to get wet with excitement.
John was a little surprised when Mark suddenly pulled his cock away. His mouth hung open and John leaned forward trying to follow his missing prize, like a fish chasing a lure. But he soon felt it return when Mark lifted him off the ground and impaled him with his throbbing dick. The pleasure was immediate and intense, and John couldn't help but moan. Each time it slid up and down his vagina he felt waves of erotic bliss. His vaginal muscles contracted, squeezing tightly around Mark's cock trying to milk it and increase John's own ecstasy.
It was the most erotic experience of his life and to say John enjoyed it would be an understatement. But the old man who had sold him the gender changing lotion had warned him not to have sex with anyone. And especially not to let anyone ejaculate inside him when he was a woman. It would make the transformation permanent. As much as he enjoyed the intense fucking and wanted it to continue, John didn't want to spend the rest of his life in this body.
"Please.... pull out, " said John almost in a whisper.
But Mark didn't hear him. Or didn't care. It was the best fuck of his life. John's pussy was so tight and responsive. He reached up and squeezed one of John's large breasts, enjoying the soft feel of its skin and the flesh underneath. John gasped with pleasure. It sounded like he was really into it, too. Mark continued to pump, but he couldn't hold back for long. He soon exploded, releasing an impressive amount of seed into John's womb.
Mark slowly pulled out of John, exhausted but satisfied. This was not how he expected his tutoring session with John to go. He hadn't really learned anything for his class and he doubted he would pass. But Mark didn't care. This was definitely the best tutoring session he ever had.