"Huh. Well, it is not exactly what I was necessarily expecting, but I can still roll with this. I am a bit shocked though. I had a feeling you wanted to fuck a guy, but... if what I am feeling is what is going to happen next, then this will definitely be quite the experience to say the least."
You look at your former girlfriend with mixed feelings. He was your girlfriend, and you had a feeling something like this would happen, but you had no idea what would happen next. You apparently have sone deep sexual fantasies that even you yourself didn't quite realize. "Um... so what happens now?" You ask.
"Well, I guess we will find out right now because I can no longer control my body." Says your former GF.
You realize neither can you as both of you start stripping your clothes. Then your GF's body grabs your arms and literally pulls you up into the air and spins you around until your facing away from him. Finally, in one swift motion, he yanks you I to the air a bit, grabs your hips and plants you down on his cock until it is balls deep into your ass.
It really fucking hurts. His huge cock is jammed up a place it never was meant to be all at once. But after the initial first several thrusts, the pain then slowly starts to turn into nothingness, then numbness, then pleasure. Not a lot, but enough to make the pain a bit more bearable.
"Um... is this supposed to be happening?" Your former GF asks you. You cant really speak because of the pain in your ass, but you look a d find that your ass is pushing out into an almost donut shape, kind of like how a horse's looks. "Oh shit! I think I am stuck inside of you now!"
You cant see what he is talking about, but you can feel it. A solid ring of something hard has encircled his cock, trapping it inside of your ass. He can push and pull it quite a bit in and out, but the head is locked inside. You also realize that your feet haven't been touching the ground for a few seconds now. That can only mean one of two things. Either he is getting taller, or you are getting smaller.
Turns out that it is the latter of the two. You are smaller for sure. Your cock also is smaller. Your balls are the size of raisins now, and your dick could have a difficult size challenge against a baby carrot. Your ass also feels like it has a lot more cushion to it.
"Damn, you know, for your first time doing anal, you massively drew the short straw. But wtf is up with your fetishes man? This is your fantasy, and yet you wanted to be impaled like that, no lube or anything? Either way, you ass feels amazing, even if I now have to carry you around with me everywhere like a cock sleeve. By the way, you may want to look in the mirror. Is it just me, or are you kind of... girly looking now? As in, you have an actual ass now, and your chest seems to have a few extra layers of fat behind your nips too. I would check for you, but I still have 0 control over myself." Says your former GF.