She lets Stacey in the stall reluctantly

After a second, Krissi realized there was no alternative. These magic marker psychos could do anything they wanted to her. Krissi unlatched the door and Stacey strode in, then shut it behind her. In the cramped quarters it took only a second for Krissi to realize that Stacey had altered herself. Seeing the look of shock on Krissi's face, Stacey cackled in delight.

"You know, I saw what Finn was doing to you and I just couldn't help but feel jealous. I wanted a piece of fine tight ass too! I'll even show you what I wrote. I know it'll be right up your alley."

With that Stacey pulled her the top of her shorts down enough to reveal the thick black letters right above the fuzz of her pubic hair.

MONSTER COCK AND CUM FACTORY BALLS.

The elaboration hadn't really been necessary, because the shape of the python in Stacey's shorts was clearly visible through the thin cotton fabric. Her shorts had already been tight enough to show off her yoga-toned ass and thighs, but now a tumescent, veiny penis strained them obscenely. Krissi gaped and tried to back away, fearful of what Stacey might try but determined to resist.

The absurd rod kept hardening. Impossibly it seemed it still wasn't full size yet. Krissi put up a hand as if to push Stacey away, but didn't touch the other dickgirl. Then Stacey bit her lip in determination, braced her hands against either side of the stall, and flexed her abs hard, like she was doing a crunch. With a sudden tearing sound the strained seams of her shorts tore, and her full monstrous cock burst free. It was larger than anything Krissi had seen in porn, especially in girth. Thick veins wove around it, and she could see it pulse in time with Stacey's excited heartbeat. Stacey finished ripping her shorts off by hand to reveal a pair of hairless balls, each the size of a chicken's egg. She still wore a thong, pushed aside completely by her mighty weapon.

"Holy shit! I didn't realize just how big it'd get, isn't it amazing?" Stacey said, giddy and malicious.

Krissi simply cowered in the corner of the stall, trying to keep from shaking or letting too much of her fear show. But her eyes were glued to Stacey's cock and a treacherous voice inside her was whispering about just how much sweet, satisfying cum those enormous balls could give her.

"Oh, my sweet cumwhore, I know what your dirty little mind is thinking," Stacey said as she produced the Magic Marker, uncapped, "But this time I want a little more fight from you."