...one where he was a girl. He'd wondered a lot about what it felt like for girls when they felt horny or touched themselves, and what he'd be like if he'd been a girl, plus he wasn't sure he felt ready for full-on sex, so that seemed like a nice place to start.
As he clicked it, he seemed to shoot through a white void towards the fantasy, and as he flew, he saw his clothes melt away and his body change to that of the girl version of himself. His proportions shifted around as if he were being moulded from clay by invisible hands, his chest swelled out into soft breasts which felt unfamiliar and intensely sensitive, and his penis and testicles shrank into his body and reformed into parts which felt totally different.
Everything went a bright, blinding white for a moment, and then the fantasy appeared. Something immediately clicked- everything felt different. Andrea looked down at her body, and for a second didn't even register that her gender had changed. She peered past the large soft chest she now had, and saw only a small protrusion from her crotch where his cock and balls had been. She felt a tiny nub at its top, and curiously reached down to rub it, only to yelp in surprise at how sensitive it felt. This was her clitoris, she realised, and as she more carefully reached further down, she found a moist opening between fleshy lips- this was her vagina.
Her finger started to rub the moisture around, and she felt pleasure start to mount, as well as regaining focus on what this must mean. Since she'd become a girl, she had a vagina to be fucked instead of a penis to fuck with. Her mind started to fixate on penises, and she felt more moisture build up as she continued to rub herself carefully. She supposed it was only natural- as a boy he'd been mostly attracted to girls, so as a girl she was mostly attracted to guys.
Lying back, she allowed herself to indulge in the fantasies. Her finger carefully pushed between her pussy lips and she panted. She wished it was a man, a male, a penis. Her thumb cautiously moved upwards and brushed along her clitoris, and she moaned eagerly. So if she touched it right, it felt really nice.
Her other hand decided to explore the most visible difference between her and him- her breasts. It reached up and cupped the soft flesh, and her heart raced, wishing it were a boy playing with them, imagining the pressure of his large hands on her. Her thumb and forefinger reached for her nipple, which seemed sensitive and erect, and pinched it. Another moan escaped her lips, amazed at how sensitive her chest felt when he had never even thought of his in a sexual way.
Having established to herself what felt good, Andrea continued to pleasure herself eagerly, and more fantasies of handsome men around her played on her mind. She imagined sucking cocks, having cocks fuck her tits, guys sucking her boobs or eating her out, getting held down and pounded in the pussy.
Something that surprised her was that as she shut her eyes in pleasure, a voice she recognised as her own in this body seemed to monologue to her, and before her eyes she saw himself turn into a girl all over again. "Don't you see how much nicer it is to be a girl?" it said. "You don't have to be a boy anymore. In fact, I don't think you want to be a boy anymore. Just allow yourself to be castrated. Can you feel yourself getting emasculated? Your testicles are turning into ovaries- you won't be impregnating anyone anymore, you'll be getting impregnated. Your penis is turning into a little clitoris- instead of pleasuring people, you're going to be pleasured. And your vagina is forming- I hope you're ready to be impregnated. Look at those nice juicy tits you're forming. Anyone would love to suck on them."
Now she'd finished transforming, the fantasy and the voice turned from transformation to sex. "Ooh look, here comes a handsome man. Look at that big juicy cock, all hard for your beautiful body. Feel him pushing inside you? I bet it feels amazing. He can't hold himself back, he's starting to rail you. I can tell you love having his thick shaft fill you up. His balls are slapping against you- what's inside them will soon be inside you, and I bet you can't wait. His big firm hands can barely fit around your boobs, but I bet they feel amazing touching you. Especially now he's pinching your nipples. Nice, now he's fucking against your G-spot. You're both so close now, I bet. So cum. Embrace the girl you've turned into, and cum. He's certainly gonna. Oh nice, now he's hit his peak. His warm seed's flowing inside you- there's so much of it, I just know he's gotten you pregnant. Go on, Andrea. Cum. Enjoy the best part of being female. You've earned it. You're such a good girl."
Andrea did as the fantasy told, and felt herself cum intensely hard. Her whole body seemed to shake with pleasure, and it almost literally felt like she'd been cummed inside by a guy as her juices flowed and her slit clenched around her fingers. Once the high subsided, her eyes stayed shut as everything went white and she shot back to the void she had started in.