A glamour potion

Eventually she retrieved a second vial from her robe, this one containing a suspicious looking green fluid. Of course, she had never once stopped talking. "...so when I left the academy, I figured I'd probably have to sweet talk a lot of men. You know, just to get a better price on a room at the inn, free drinks, that sort of thing. So I got this glamour potion. Well, I mean I got my sister to make it for me. She's good at that, which is why I have so many potions. But I've hardly used this one at all, because actually it doesn't really work for me, and I was thinking that didn't make sense because my sister is really good at making potions like I already said. So I was reading this book about potions, and it said glamour potions give the person who drinks them their ideal body appearance, so I was thinking maybe it didn't do anything for me because I like my body like it is, so maybe it would work for someone else, like maybe you. It doesn't actually change your body or anything, that would be hard, but it projects the illusion of a better body on top of your real body, or at least a body that you think looks better, which is not to say..."

Having finally had enough of her babbling, I snatched the vial from her hand, uncorked it, and took a swig. The taste was about as I might have expected, which is to say it was absolutely disgusting.

It didn't really feel like it was doing anything. I opened my eyes - I had closed them when I downed the potion - to see Lyra staring back at me. More specifically, staring at my chest. Looking down, it was pretty obvious what she was staring at. I had breasts now.

Or, rather, it looked that way. Without even thinking I immediately brought my hands to feel them, only to find they passed right through to my real chest underneath, leaving a bizarre visual distortion in their wake that gave me a headache just looking at it. I quickly decided it was best to look, not touch. When I wasn't trying to touch them, though, the orbs of flesh protruding from my chest looked quite real. They moved up and down with my breathing, and the surface was indistinguishable from my own skin. Just seeing them there was strangely satisfying. And also very arousing.

I felt myself begin to stiffen down below - which was rather surreal because I couldn't actually see it happening. My entire body looked like that of a woman, a lithe but curvy one. The only part that didn't look quite right was the spot between my legs. It was still distinctly female, but it just looked... wrong, somehow.

Apparently noticing the same thing I was, Lyra found her voice again. "That's weird. I wonder if it's just that you don't have a clear mental image of what that part should look like, or if your erection is causing a distortion like your hands did before. Still, it definitely works, right? You're seeing the same thing I am?"

She hardly needed to ask. The illusion was apparently adaptive enough to show signs of my arousal. My nipples appeared hardened, and I could see but not feel a drop of moisture trailing down my thigh. I wasn't in the mood to talk, but I managed to get out a breathless "thank you" before jumping on her.

I can hardly even remember what happened after that. I mean, we had sex, of course, but the details are hazy. I wound up lying on my back as she rode me like a horse. I couldn't bear to look at the place where our hips met, the distorted effect was downright nauseating. But I didn't care, I had not one but two heaving bosoms to admire. Not to mention the exquisite feeling of entering a woman for the first time.

I'm pretty sure I reached climax twice before Lyra was satisfied. Had it gone on any longer I probably would have been in pain. As it was, I felt terribly drained. It was only moments after she fell down beside me that I started to pass out. As consciousness slips away, I hear her speak, barely comprehending the words...