"Oh, man, that feels incredible." Derrick moaned as the rough tongue slid over his crotch sending erotic sensations through his whole body. As the slobbery attentions continued, the intense pleasure shifted, slowly sinking inside and closer to his anus. The boy shivered, a little confused, but enjoying the experience too much to try to stop it. Besides, this was a huge lion - what could he do about it?
The beast finally stopped, and Derrick sagged, sexual need built to the point he felt hot and slick, at the point of climax. Realization finally dawned and he reached back suddenly to feel his crotch. When his fingers did not find the male parts he expected, they slid around to his but crack and found the source of the intense sexual desire. So did the lion. With a sudden lunge that pinned Derrick against the mattress, the lion mounted the boy with a deafening roar. Derrick cried out in surprise as the animal cock rammed home and was shoved inside his new cunt. That belongs to a lioness, thought Derrick. The male was huge and heavy, and each thrust sent a throb of pleasure through him. He gasped as his hands pulsed, fingers merging and palms swelling, and arms developed golden fur.
When the beast came, Derrick gasped and grunted in orgasm, fully female inside. Two, three ejaculations, and then the lion dropped on top of him, the barbed cock still buried deep. Derrick was panting, his arms and hands not the forelegs and paws of a lioness. He could feel a tail twitch, and was sure his hindquarters were fully transformed as well. but his chest and head were still human. Was the lion going to leave him...
As if to answer the question, the lion withdrew, and then mounted him again. Derrick could feel his insides twist and change, his bones adjust, his whole body becoming different. Once more the lion came, jetting hot seed into the newly created female parts. This time Derrick roared as well, his face pushing out into a muzzle with the sound, finishing his... her transformation into a mature lioness.
But the male was not done yet. He lay on Derrick, licking the back of her head. She felt new instincts building, found the lion's scent not only familiar, but commanding. She was his. It did not matter that she had a human life to live, that she had a family, that she did not want to spend the rest of her life as a beast. She belonged to the male, was a member of his pride, was a lioness destined to bear his cubs. That knowledge outweighed everything else.
And then the male mounted her a third time, and they roared in mutual lust and desire and instinct. When the mating was done this time, they licked each other clean and then padded off to the woods. Derrick did not know what would come next, although she did know she was now pregnant. For now, she would follow the new animal instincts and see what happened.