In spite of the awkwardness of your night at the reservoir, your marriage plans have gone off without a hitch. The next morning you and Sam give your father the good news, and though he makes a bigoted comment about "traditional marriage", you let it slide so as not to ruin the moment.
A month later, the two of you were wed. Soon, you would start learning the ropes at your father's business, and Sam would be heading off to college, but for now the two of you had a week alone at a cabin your father rented for the two of you. And during that week, Sam intended to get something important out of the way...
It was the morning of your second day at the cabin. The previous night's passions had been a blur to you. Sliding your dick into Sam's vagina felt like that night at the reservoir turned up to 11. And they said sex with a full woman was even better! Turning over in bed you noticed that Sam was already up and in the shower. A few minutes later he, soon to be she, emerged.
Sam's breasts had begun to grow. Your seed had obviously taken last night and her change was starting. "It's started, and I'm so fuckin horny", Sam said, smiling. Let's go again, c'mon Ty. Sam walks over to where you're standing at the side of the bed. You reach out to squeeze his breasts, but to your surprise Sam gives you a shove, knocking you back onto the bed.
"Oh c'mon, you're supposed to be the big strong man in this relationship." Sam said flexing his now less visible muscles. "Come and take me!"
Rising to Sam's challenge, you rise back up and grapple with him. He's clearly weaker than before, but still just a bit stronger than you. However, the longer the two of you struggle the more you'll catch up. As you lock hands with him you think you can actually see his breasts swell. They're at least F cups now. The rest of his body has been changing as well; his hips have flared out wide, and his butt has gotten quite large as well. His face is stunningly beautiful, complementing his thick brown hair, which he has been growing out.
Finally, you gain the upper hand in your struggle as the last of his visible muscles recede. You notice that Sam, no Samantha's former dick has expelled its last load of cum and is lying hardened on the floor. Seemingly strained by the ordeal, she gives up and flops forward, leaning her now massive breasts onto your tiny ones. Feeling them against you, you estimate that she got the maximum possible growth.
"Well, since you want me to play the barbarian..." you say, lifting her up and holding her over your shoulder.
"eep", she exclaims, clearly not used to being this delicate. However she calms down as you gently rest her back on the bed.
"Well, the big strong man has made you his woman. What now?", you say as you slide up on top of Samantha.
She responds by pulling your head down onto her chest. It seems she's still fairly strong, which is understandable given how muscular she was as a man. "Oh no, whatever shall I do now?" she says playfully. You pick a nipple and begin sucking on her breast, eliciting a second excited "eep", followed by a deep moan. She's definitely having a good time, and now it's your turn. You line up your cock and enter your wife's vagina for the 2nd time in as many days.
You had sex last night, yes. But that was different. Last night you had sex with a man. One with an androgynous face and a hard, muscular body and stiff, firm breasts. Today you're having sex with a woman. One whose soft body has grown both bigger and taller. You sink into her massive breasts and soft thighs as if you were hugging a cloud, thrusting with more vigor than you did before. The two of you end up making love all day that day, and the next day as well.