You barely notice anything's changed for a minute or so. You do notice your uncomfortable morning wood, though, and pull up your underwear to see your pointlessly stiff cock. Ugh, you hate dealing with this thing sometimes.
A twinge races through you as your body responds to this thought. Your cock twitches and starts to shrink, and under it a sucking sensation fills your crotch, your balls seeming to slip inside you. You groan in an oddly high-pitched tone and feel your body convulse as it develops curves and your arms and legs and hands and feet decrease in size. Your chest feels odd now, and as you pull off your shirt your nipples perk up and enlarge in the cold morning air. In perfect sync, your sex characteristics invert: your by now shortened penis recedes to a tiny, sensitive nub, a slit forms at the centre of your scrotum and connects to a vaginal passage inside you, and your chest enlarges into soft but distinctive breasts.
You look at yourself in shock, disbelieving of what just happened. You're a guy, how can you have turned into a girl?! You pick up your phone to see a text from your girlfriend, anxious about how she might react to hearing about your sex change. But you see two sexy messages. One is a nude of her as she always looked before, with the focus on her vagina but most of her body visible too, with the text 'She wants you...' over it. The other is a close-up on her pussy, with a caption that seems confusing for a moment until you hear her groan and grunt in a deeper tone as it seals up, two lumps move inside it and the clitoris expands until it forms a 7-inch penis- it says '...and so does he!'
Confused but admittedly aroused by both the bodies you've just seen, you look up 'sex change' and find a lot of things like tutorials for how to make your body's sex change at will, how to resist a sex change, even a sex-ed video for school kids. You click the latter, figuring you could use the simple explanation, and with a bunch of accompanying diagrams the narrator explains how sometimes your body will want to be a different sex, how it can change, that that's totally normal and some ways to deal with it.
So that's... a lot. You wonder what to do when another message comes from your girlfriend. "Do you wanna see him or her when you come over?" she asks.
After considering, you reply...