You feel your body start to change. An odd and uncomfortable feeling starts around your chest. Your breasts slowly shrink- To the point where your bra is no longer needed. The sensitivity within them slowly starts to fade away, as your stomach starts to feel tight. Your hips become less narrow, as they become wide. A stress builds by your stomach, as more muscles grow around your previously slim waist.
Besides that, your hands feel more strong as well. It seems the strength changes are affecting your arms and legs, too. While you don't feel as if you could possibly lift, say, an entire ton effortlessly, you certainly feel that you can pick up heavier objects more easily. Just not to the point of being a superhuman. Your legs and arms feel exhausted from these new muscles growing. Due to your body adjusting to this, you fall to the floor, unable to escape this cursed hallway.
It's then you feel a painful, yet pleasurable, sensation in your crotch. You feel your clitoris start to expand, as it forms into two testicles. Just then, you feel that something important is missing- You feel around your crotch, attempting to ignore the sexual satisfaction you get from touching your testicles. It's then you feel your panties start to become weirdly tight. It's then you realize-
...Your vagina has vanished in favor for a penis. You feel it fill up your panties, as your clothes, your pants, specifically, start to feel as if they are a bit too small. The penis, despite feeling complete, keeps growing. It makes your panties feel unbearable, as they slip by your penis. It's uncomfortable. You're forced to take your pants off, leaving your bottom bare. Then, there's one final thing-
Your penis starts to erect. A sexual pleasure surges through your body, causing it to rise. You groan in ecstasy, noticing that your voice has grown much lower than it originally was. After a few moments of bliss, you finally orgasm, leaving clear, wet cum on the floor. You now have the complete body of a young man, strangely enough. Well, this day was already weird enough, after all. No wonder such a thing happened.