A big dick of course.

“Okay, give me a huge dick.”

“How big?” Jane asked.

“10 feet long.” John typed amused, completely in disbelief about what was happening.

The word ‘error’ appeared in red. “Mmmm, sorry Johnny. 10 feet defies the possibilities of the human body. Can’t do that.”

John smirked, feeling his disbelief to be proved right. “Fine, give me the biggest dick you can.” He typed.

His own typing blinked green. John felt his stomach begin to churn and a pounding sensation rise in his pelvis. Miraculously his crotch felt like it was expanding. His cock began painfully straining against his underwear. He heard the fabric of his pants being stretched under his desk. His cock began to snake out of the leg hole of his underwear. John was in agony, his length growing rapidly. It finally stopped. John could feel the head of his cock touching his bare knee inside his trousers. He did his best to keep a straight face, but a few classmates glanced back at his muffled groans. Luckily he sat in the back row and no-one could see the massive bulge in his pants.

“What the fuck! This is real?” He hurriedly typed.

“Yeah baby. Its real. All 15 inches of it.” Jane responded.

“15?!” John responded. He looked up at Mrs. Chanelle in her tight black dress. He had always had a crush on her, she was gorgeous after all. She was mixed race, had a gorgeous hazel eyes, full lips and a voluptuous build.

Suddenly he felt light headed. “Whats happening?” He typed furiously.

“All the bloods flowing to your dick, dude. Turns out a dick that big is actually kind of a bummer.” Jane retorted.

“Well, make it stop.” He managed feeling his pipe beginning to consume him.

“Gotta be more specific…” Jane said.

John thought he might actually lose consciousness. He pulled himself together as best he could. “Make my dick as big as it can be while still functioning like a normal penis.” His words blinked green.

“Ehh... terrible phrasing but okay, I’ll take pity on you. That will do.” John immediately felt relief.

His cock shrank in his pants a few inches. He could still feel it press against the inside of his leg, but he was experiencing minimal discomfort.

“Your dick is now 9 inches flaccid, and 12 hard. You’ll probably want to be more careful with your third change John.” Jane told him.