Jenny opened the message from inside the cookie and read it:
"#6: Your breasts are big as is,
Quite a sight for sore eyes.
But now they will grow up
To an enormous size.
But despite their new growth,
You can still cross the floor.
For each boob will somehow
Weigh less than before.
They'll be super-squishy,
And can take quite a hitting.
(And in case you forgot,
Your nipples will keep shitting."
"What th-" Jenny couldn't finish her sentence before a rush of pleasure overcame her chest, making her stumble backward onto her bed. Her breasts began to swell, and somehow Jen was swept away by this feeling enough that she couldn't help but stick her hand down the front of her diaper to rub her crotch. She moaned, her breasts growing larger than basketballs and showing no signs of slowing down. The whole process was actually fairly quick, but to Jen it felt like an hour, constantly in pleasure as she furiously masturbated, not caring that she was pissing and shitting during it.
Eventually, Jenny achieved climax, crying out as her breasts reached their final size. Each one was slightly more than half her height, small enough that they wouldn't drag on the ground but big enough that she wouldn't be able to fit her arms around them. Her shirt had long since been destroyed - actually, it seemed like it had vanished - , but her diaper-bra remained, bigger to match her also-larger nipples. Panting, Jenny stood up shakily, and quickly realized that, indeed, her boobs were somehow lighter than normal, despite being several times larger, and they didn't seem to sag at all. Curious about the third verse, she poked the side of one of them and was surprised that her hand could sink into the breast very easily, as if her breasts were like gelatin, and they would regain their regular shape once she pulled her hand out.
"Wow..."
"Wow what?"
Jenny jumped and turned around, almost smacking Susan with her new breasts. "Wha- how long were you behind me?"
"Just a couple minutes," replied Susan. "You were really getting off, and, uh, I didn't want to disturb you..."
"You could have said something!" Jenny then considered... "Wait, does that mean you saw..."
"Saw what?"
"You know, before I started..."
"I'm not sure what you mean, Jen. You looked like you had just gotten back from changing, and then you suddenly started moaning and touching yourself..."
Jenny blinked. That's right! Kyle had said that no one else would acknowledge the cookies' existence!
Susan started talking again. "Um, Jenny..."