I wondered why I was letting myself take advantage of this unwitting woman. It wasn't like me at all to hurt others and what I was doing was not much better than rape, even if she thought she wanted it. But for some reason I couldnt bring myself to stop her as she undid her bra and let it fall to the floor. It's been said that absolute power corrupts absolutely and I guess they were right. She quickly slipped her underwear off and stood before me completely naked. I grinned as she leaned over and started to unbutton my shirt. My shirt slipped off and she deftly unbuttoned my pants. I pulled them off for her and let her slip my underwear off, but as her hands brushed my penis, I ejaculated prematurely into the air. She looked at my spent unit in disgust and sat on my bed with a sad look. I sat next to her and said, "What's wrong?" She answered, "You're spent, but it doesnt matter, that little thing wouldn't be enough to get me off anyway." She spoke as though she found nothing odd about her current situation. I asked, "Why are you so intent on screwing a 16 year old you dont know anyway?" She looked at me and shook her head, "I dont know, I was just overcome with the most intense sexual desire, and it wont go away, but there is no way you can get me off with your unit. No offense." I grinned and said, "Well, hypothetically speaking, how big a dick would you like a man to have?" She looked at me oddly for a second, but said, "As big as it can get, I'm talkin hung like a horse." I grinned and said, "Well, then I wish that you wont find anything unusual about anything I do or say from now on." She looked at me strangely for a second, then the look went away. I continued, "I wish that my penis was like that of a full grown horse." I looked down at my crotch and watched my penis slowly expand, the feeling of it's growth excited me immensly. Strangely, the skin began to darken and become splotchy, at the same time, the base was enveloped in a furry sheath. Finally my ballsack became dark and leathery and moved a little farther toward my ass. I really did have the cock of a horse. I looked at her and asked, "Still wanna have some fun?" She nodded and I moved her farther onto the bed. I carefully positioned the huge cock tip on the lips of her sex and slowly pushed it in. She squealed a little in pain as my huge cock stretched her vagina to the maximum. Once the head was in, I made a decisive shove and buried myself to the limit of her depth, which ended up being about half of my length. I said, "I wish your pussy had the internal depth and musculature of a female horse, without changing your outer appearance. With that, I felt the pressure around my cock lessen a bit. I slowly eased out till just my tip was inside, then thrusted again with all my weight, burying the full length of my massive unit in her as she moaned in delight. I tried to pull out but she tightened her strengthened muscles around my unit and I could not move it at all. She giggled a bit at my predicament as I tried to pull out she squeezed it tighter and tighter. I thought for a second she was gonna pinch it off, then she released, and I began to thrust. The pleasure built up in waves and finally after a couple minutes I climaxed, I tensed up and buried it as deep as I could when I finally came. She once again held my penis hostage with her stong pussy muscles. She said, "That was great, but I'm not done, find a way to give me MORE!." I grinned and said, "I wish that you would become my 16 year old girlfriend but keep your breasts and pussy developed the way they are. I also wish for you to be released from the need to have sex with me constantly, but instead to need it at least twice a week, or whenever I feel like it." She suddenly shook her head and released my unit, I pulled out and sat on the bed as I watched her slightly aged features disappear and get replaced by a youthful complexion. She grinned at me and said, "I better get home now, seeya tomorrow afternoon." I smiled and nodded as she walked out, I wished for her to become a normal student enrolled in my school and for no-one to remember her old self except me. This would be great...