I finished eating my lunch right when the bell rang, and I walked to my next class: engineering. We were always doing projects in that class, and never really working. As I walked in and saw the instructions on the board, I realized today would be no different. Our teacher was crazy scatter-brained--but then again, what good engineering teacher isn't? As the last of my classmates lagged into class and the final bell rang, the teacher began by saying, "Alright, we're going to begin a new project now. I've devided your class into two groups--" He was instantly cut off with a groand of disappointment. "Now, now, you remember how it went last time I let you chose your own groups! That was chaos. We can't have that happening again."

With that, he turned around and began writing on the blackboard.

"Group one will be you," he said, pointing his chalk at me, "Hannah, Natalie, Abby, and Jessica. Group two is the rest of the class. I know the groups are uneven, but group 1's task is a lot harder to do with lots of people. You'll see a design brief once you've broken up. Now, get moving!"

I slowly sauntered over to my group's table. I was glad I'd been paired with several girls that I had a crush on. Like I said earlier, they were all 5' tall when they weren't excited. Hannah was pale with orange hair and freckles. She had decent boobs, but a killer ass. Natalie was very tan, like a dark Indian tan, with black hair. Her body was a nice shape, and she had a decent ass and maybe slightly bigger than normal boobs. Abby was a little tan, and had long light brown hair. She had fairly big boobs, and a decent ass. Jessica was the odd one out in my group, with almost no body to speak of. She was asian, with black hair and a skin color between Abby's and Natalie's.

As I reached the table, the girls were all standing there waiting for me. As I predicted, Hannah was taller than the others by about an inch. She was always kinky. The other girls weren't more than a half inch or so taller than normal, if at all. All of the girls were no taller than my chest, and I towered above them.

"So," I said, trying to appear nonchalant, even as an erection grew in my pants, "what's our project on?"

"Well, you'll like this one!" Natalie said, laughing. I just stared at her, confused, and walked to look at the packet our teacher had left us.

"MAKING CLOTHES FOR CHANGING SIZES"

"What makes you think I'll like this?" I asked her incredulously, holding up the packet.

"Keep reading," she said, and errupted in giggles again.

I kept flipping through until I got to a part that said "You must experiment the standard change in size for group members and demonstrate the clothes on them; at least one per gender. For males, this should included extreme height jumps."  "Extreme height jumps" or EHJ was a euphemism for when you cummed. Because when you cummed, you lost several inches in height at once. And the extreme height jumps lasted up to a whole day, and never less than an hour.

As I finished flipping through the packet, the teacher announced, "You have two weeks to work on this. I want to see good results!"

"Looks like you're trying to make this easier on us!" Hannah said, noting my erection, evident by the fact that I had already dropped to 6'3" tall.

"Whatever," I said. "So are you all. I mean, are any of you still 5' tall?"

Jessica laughed sheepishly. She was known to be shy, but right now she was actually the tallest of the girls, at about 5'3" tall. At that point, the top of her head reached my chin, just about. The other girls were all about 5'2" tall. With the basic small talk out of the way, we set about "preparing out data," as we called it. In other words, seeing how much we could get out height to change, and for me, withough cumming. I found that I pretty muched maxed out at a minimum of 6' tall, and it was tough to reach that without experienceing EHJ. The girls took longer to get accurate measurements. I didn't want to intrude on them pleasuring themselves, so I just waited at the table. They came back reporting that their natural peaks (not drug induced, like stimulants) were between 5'6" and 5'8" tall. I could tell when they came back that they had been busy. Even though I had reverted back to my full height, the tops of the girl's heads now reached the bottom of my lip.

"Now for the final measurement," Abby said seductively, walking over to me.

"What?!" I said, a little shocked by her forwardness. "I-I can do it on my own, thanks."

"No, no, don't be rediculous," Natalie said, as she also began to advance towards me. I began backing up, and soon, all of my group followed chase. The girls cornered me in the back of the classroom. By now, I was a little excited, and was down to 6'3" tall, making the tops of the girls heads about eye to nose level on me. Finally, the girls reached out and two of them pinned my arms against the walls.

"Calm down," Natalie cooed cooly as she unzipped my pants and slid them down my legs. She bit the tip of my dick between her teeth and began to suck vigorously, until I burst with a rush of pleasure. I could feel myself dizzying as I shot my load into her mouth. Unlike what I expected, Natalie gladly drank it up.

My face turned red as I ashamedly pulled my pants back up and fumbled to button them back up. I looked back up after finishing with my pants, and realized that I was almost eye level with the girls now. I figured I was about 5'11" tall, because now the top of their head was over my eyes, but there eyes were about at my lips. The girls were all giggling at me, and Natalie was happily likcing her lips.

"So, data!" Abby cheered. "Shrinkage: about 4", after factoring in his dick's growth."

"I look forward to collecting more data," Natalie said lustilly. Suddenly, she began to grow, an effect of eating the cum. Once she was done growing, she was taller than me by an inch, at 6' tall. It felt so weird to look up at her, even if it was just a little. She leaned down, almost intentionally, like she enjoyed making me feel short, and hugged me. "Thanks for being such a good sport about this," she said, patting me on the back.

Not long later, I returned back to my desk. I would be stuck at 5'11" tall until whenever I began to regenerate my height. For whatever reason, if you cum, you're stuck at the height you're at after cumming until it all regenerates, rather than just growing back to normal and not having the couple inches lost to cumming. Just in case we weren't back to normal by the time we got home, my engineering teacher us all notes explaining the current situation.

As the final bell rang, I walked out to my bus, sat down, and rode home in silence. I got those looks everyone gets when people know they've been pleasuring themselves. Once I got home, I was only 6' tall, but my parents understood the situation. They definitely weren't what you'd call ecstatic, but they understood. With that, I ate dinner, did my homework, and went to sleep, sort of looking forward to and sort of dreading tomorrow.