You decide what you want to try quite easily. You may have gotten yourself to orgasm from playing with your clit, but you sort of just felt like a man with a vagina when you transformed yourself like that. Now you feel totally like a woman, and you like the idea of indulging your new self's desires and fantasies.
You lie back on your bed naked and pull out your phone, wanting to look for some smut to get your figurative (actually literal now!) juices flowing. Without hesitation, you type in 'big cocks', and then you feel surprised at yourself. Wait, what? You were straight as a boy, so why would that be what you're drawn to?
Ohh. If you're straight as a boy, you're straight as a girl too. And you realize thinking about what you'll see when you search that is turning you on. Your nipples have gotten hard, your clitoris feels erect and you feel moist between your legs.
The hesitation from the boy you were is rapidly fading, and you hit enter on the search. The results are breathtaking to your feminized mind, and as you look at the assortment of large firm shafts you've found, your hand moves down to rub at your clit and stroke your moistened slit, your fingers preparing to push inside it.
Horny feminine fantasies are racing through your head as you put the phone down, start to massage your breasts and shut your eyes. You get mental images of boys above you, their cocks thrusting between your boobs eagerly, shoved down your throat as you take in the warm salty tang of manhood, mounting and pounding you to rub as deep inside your pussy and ass as possible, their virile balls pressing against you aching to fill you with their cum, and if they do it in your pussy, fertilizing your pretty nubile body.
An odd fantasy soon comes to you. You were a boy before, and you gave that up. To think you used your power to transform your sex, to emasculate yourself, and this feels even better. It almost feels like the female version of yourself is taking precedent in your mind as well as your body. As you hit your peak, for a moment you feel like you never need or want to be a boy again- you have been castrated and now all you want is to be fertilized! You need someone to fill you with his seed and impregnate you! This form is perfect, it feels perfect!
You pant loudly as your orgasm subsides, and the world irises back in on you. Wow, that fantasy got pretty intense, you think to yourself.