The transformation gains momentum

So spurned on by Heather, Adam needed no other invitation, didn't need to be asked yet another time.

He climbed on top of her, he mounted her, albeit with quite a bit of difficulty. It took some effort to bend to his rock hard shaft, by now already more than a foot and a half long, and to align it with the entrance to Heather's overflowing pussy. When it was done however, the reward was a gasp from the girl under him, as she felt the swollen red mushroom tip spreading her outer lips. His intention had been to push in slowly, to give Heather a chance to accommodate his increased girth, that was already stretching the entry to her cunt obscenely. What he did however, as he forgot to consider his new found strength and increased prowess, was to to thrust in with such a ****, that his hulking erection buried itself more than halfway inside her love channel right away, accompanied by a cry of ecstasy from Heather. This intense experience caused her eyes to roll back as her body spasmed and her vagina contracted around his incredible length and girth.

While Heather was unresponsive to anything but the peak of her pleasure, Adam used the time to get a good feel for the mass of flesh that were her expanding knockers. Already in their original state they had been quite impressive and one of the most prominent features of Heather's curvy body that just radiated of sex. All natural 38E cups to be exact, paired with a body of 5.5 feet height, the size of her tits had left no doubt that Heather was absolutely stacked. Now they were not only slowly expanding, but it seemed that Heather's orgasm had caused a sudden spike in their growth, an increase by several cup sizes. Adam felt mesmerized, bit down and suckled on the rigid and stiff nipples that crowned her marvelous melons.

When she came down from her temporary high, she noticed it as well: Her breasts were growing more than considerably. They were growing to become enormous. While Adam played with them, each of them individually already looked bigger than his head. Heather smiled in bliss, not only because of their increase in size, but also in sensitivity. And it got her thinking. How much Growth X had she actually swallowed? Would she be be able to keep up with Adam's growth after all?