As you sit on your bed and your enlarged penis slowly goes flaccid, you think about your rack. Your breasts were currently 7 inches in circumference around their widest part, or just a bit above 2 inches in diameter each. Just barely big enough for them to stretch your shirt and to smush them around your monstrous dick, but after what you just felt it wasn't enough: You wanted to engulf it.
So you focus on your breasts, wishing them to be 20 times larger, and you start feeling a heat envelop your rack, and suddenly you release a moan. Your breasts start swiftly growing, as does your arousal, quickly passing basketball-size and becoming even larger. Their growth slows down as they reach their final size: a whopping 140 inches in circumference, just barely below 12 feet each.
You sit there with a smile in your face, marvelled at your massive, beachball-sized tits which you can barely wrap your arms around, as they sit on your thighs. You start patting them, making soft slapping sounds, then you pass your fingers across their length, and finally you attempt to lift them by cupping them with both hands: they're deliciously heavy. All of these ministrations leave you panting and sticking your tongue out, and then you feel it: your dick wants to join the party.
Your equally massive member begins to get erect, and its size makes its erection slowly dramatic. When its tip reaches the bottom of your breasts, you let out a moan. Your tits are so big and heavy that your dick has to fight to pierce through the cleavage, and the pressure drives you crazy. You become so horny that your penis splurts out a shot of pre-cum, lubricating its way through your chest, and a clench in your vagina makes you moan as you yearn for sexual satisfaction.
You can't control yourself as you move your hands towards your face in an attempt to calm yourself down, and in the process you start biting and licking your fingers. A sense of relief washes over you as the tip of your penis pierces through your cleavage, but it's not over yet: the party has only just begun.
With difficulty you cup your huge breasts together and press them against each other, and to the best of your ability you start humping your engorged dick between them. The difficulty and effort you have to put into the motion are worth it: it feels amazing. After some time you feel another ejaculation building up, and you start cumming and cumming for what seems like an eternity. Your pussy doesn't stay behind as it soaks your bedsheets with its juices.
Finally, the deed is done, your room is soaked in your bodily fluids and you collapse, getting squished by your breasts against the mattress. If someone enters you're going to have a lot of explaining to do. Still, you look in a mirror just to the side of your bed, the one you use to dress up, and see that all this time you have had your normal body and face, just with huge breasts attached to your chest and a massive member between your legs, with a secret vagina hidden behind your balls.
Feeling the heavy weight of your breasts that barely let you move, you ponder what to do next. You consider completing the transformation and turn into an hermaphroditic Amazonian goddess. Or maybe you could return to normal and try other transformations, or transform someone else. Perhaps if you think for a bit, you'll come up with something else, too.