It was hard for Jeff to concentrate on eating dinner, especially since his sister was now an anthropomorphic horse and nobody seemed to care, but he managed to finish the food and act cool, as though nothing was out of the ordinary. Aside from a couple comments from his mother about how she wishes "you didn't wear such tight jeans, you don't need to wear tight pants to fit in at school, you need more room for your privates," and that you "need to set a good example for your sister when she reaches breeding age," Jeff didn't talk about his enhanced manhood anymore at the table. It did, however, make him realize how hard it was to wear regular clothing. You couldn't NOT see the humongous bulge his pants made.
After going to his room, he closed the shades on his windows and changed into some loose boxers that seemed to have been adjusted to handle his horse dick and balls. Looking at himself in the mirror, he started feeling horny again. He lifted up his large meat with his left hand, however he was unable to wrap his entire hand around his cock anymore because it was so thick. Feeling the power and pleasure surge through his average 16-year old body was enough; managing to try and masturbate a penis six times the length of your human cock put Jeff over the top. He was laying down on his bed now, and his cock was so long it nearly reached his face. He could almost suck himself off, he was so long!! He was also starting to feel faint - he needed the release, RIGHT now.
Just as he was wondering if this was really what horses felt, the first explosion of seed got all over his chin and face. It didn't smell all that great, so he tried to push his cock out of the way, and it soaked his wall. He could feel his equine-sized balls churn in each pump. This nearly went on for two to three minutes - it was two to three minutes of pure sexual pleasure, or so he thought.
___________
Jeff woke up the next day, still soaked in horse cum and half-undressed. His long horse cock (more like a tube, really) lay limp across his chest, half out his sheath. He managed to get out of bed, take a long shower, clean up his body and shaft, and clean half of his room's walls and bed before his mother came knocking. "Jeff! Extraction time."
"What?" he called back through the door.
"It's ten thirty!"
The (supposed) memories entered his mind. From the day that Jeff had been born, he had had the male reproductive organs of a horse. Because his Dad had been the only known anthro horse in the world, Jeff's special semen was highly profitable, and because of the income it provided, his mother didn't have to go to work. Farmers were happy because they didn't have to go through the arduous process of husbandry with stallions. Instead, they could just purchase Jeff's semen and inject it into their mares. And if it didn't take the first time around? No problem. Jeff was a never-ending supply - he saved breeders time and money. His semen had successfully birthed several baby horses - some of the really friendly farmers even let Jeff name his "children". These memories, coming from seemingly nowhere, were flooding into his brain. It all seemed so logical now - reality had created these thoughts for him to rationalize the existence of his new equipment.
Since it was the weekend, Jeff had to extract his semen for the farmers today... and his mother was going to help him jack off?!? Like... she always had??!??!
"Oh."
This simple acknowledgement was apparently enough for her to enter his room. She was wearing long rubber gloves and holding a large glass jar.
"Do you need a couple minutes to start off? Or are you busy?"
You stared back at her, wide eyed and still half-naked. There was no way you could get horny with your mother in the room.
"Mom..."