I woke up with anticipation. The morning of the presentation was finally on. Today was the day we were going to demo our engineering project, which we'd been working on diligently for the last week or more. The girls had snuck home to their houses late at night, so I assumed they were close to their regular heights. I was proud to finally be back up to 6'6" tall, which it seemed to me, had been next to unattainabe lately. I woke up, showered, and got ready for school. As I fixed myself breakfast, my parents still not home, I also fixed Amber's waiting for her to come in. When she came in, I was relieved to find she was shorter than yesterday, for the first time in days. As she walked over to me, her hair still wet from her shower, I noticed she was actually my height exactly now, an incredicble height loss of 2' in just one night.

"Hey shorty," I said, teasing her as I used to.

"Hey, little bro," she said, ruffling my hair.

"I would check that out if I were you," I said. "Maybe you still have some sleep in your eyes."

"Oh, I guess I'm shorter. Oh well."

With that, we headed towards the bus and rode to school, not sitting together. We seperated once we reached school, and didn't see each other again until engineering. I walked to engineering as fast as I could. I had done my best to control myself all day long to make sure I was as tall as possible. I got in the engineering room to see all of the members of my group already there. Amber was down to 6' tall, Hannah, Morgan, and Jessica were 5' tall, and Natalie was just over 5' tall, maybe at around 5'2". I strolled jovially over to my group's table as I enjoyed the feeling of looking down on my little brother and my female classmates again. As the final bell rang, we began to prepare our porducts. I got in the male clothes of our group. It included underwear, so I had gone into the corner to change so that I could at least keep a little bit of my composure. I came back to find all of the girls changing into theirs. By the time I was back, they had all fit into their bras and panties, but none of them were much past that point. I figured they would be emberassed if they caught me looking, so I tried to go away, but when Jessica saw me, she seemed to not care, and actually called me over.

I was getting pretty turned on by the girls already: the tight black suits accentuated their natural beauty, and gave them a sexy sleek look. The suits were mostly unisex, other than slightly wider hips on the girls, and their stretching going up while men's shrank smaller. The girls finished changing, and we sat down to let group 1 present first. Theirs was some easy project about buildings and how they could be safe, and they had 3 sub-groups in their group which each made their own design. They present their project and sat back down.

By the time it was our turn, I was entirely calmed down, having spent the whole class thinking of the ugliest images possible. As we walked to the front, each of us dressed in out skin-tight black suits, the other group began snickering at us a little. After a minute or so, Hannah announced, "Yo, shut up!"

Finally, they all stopped talking. "This is our project," Jessica said, with a slight laugh, "on size-changing clothes for men and women."

The other group finally lost it, and burst out in laughter. After a threatening look from the teacher, they all shut up.

"Now, we will demonstrate!" Abby announced. She walked in front of me and started grinding on me. The class started snickering as I began shrinking and she began growing. Finally, she grew all the way to 5'8" tall, and I was down to 6' tall. Without giving me a break, Hannah jumped on, with the same result, growing to 5'8" tall. The process repeated with Jessica and Natalie, though Natalie was slightly taller than the other girls, at 5'10" tall. Then, Amber stepped up. Another round of laughted belted out, because my sister, who was two years younger than me, was here, taller than me, and soon to be much taller. She began grinding on me, and I grinded against her, like I was supposed to. It was one of the most awkward experiences ever--almost like having sex with your sister. She began to shoot up in height, and eventually reached 6'8" tall. At this point, most of the girls' heads came up to my eyes, while Natalie's came up to my forehead. Because of all the hormones in her body, however, Amber kept growing until she hit 7' tall, leaving her chin over the top of my head by just a little. She hugged me from behind, pressing her boobs into my back and smiling cheekily, eliciting laughter from the audience.

We lined up side-by-side and bowed. I assumed our presentation was done. However, before I could walk down, Natalie said, "Now, for the grand finale!"

I hung my head in shame, knowing what was going to happen. The girls congregated up front and drew straws. I was praying despserately that Amber wouldn't get the short straw, because whoever got that *mhm* "had" to give me a blowjob. I mean, I loved the feeling. It felt amazing. But I hated getting shorter. It was so embarassing. Finally the girls finished drawing straws. Finally, they determined that Abby had the shortest straw. She unzipped my fly, which I knew from the start had to have more purpose than just letting me pee, and began sucking on my cock. The class erupted in laughter, and my face flushed. She began sucking more and more vigorously. Finally, I felt myself reach that point of no return. I tried desperately to hold it in, but Abby, feeling my resistance, began to envelope my whole dick in her mouth and finish with one of the most amazing blowjobs I'd ever had. I coulnd't hold it in any longer. I shot my load, and she greedily swallowed every drop. I felt myself decreasing in height, with that same dizzying headache. My suit performed perfectly, adapting to my new size with few issues. I looked up once I felt the shrinking feeling cease to see the damage done. I had lost 6 inches, bringing me down to 5'6" tall, and Abby up to 6'4" tall, leaving my head eyes at her lower neck level. I began walking towards our table again, when Abby's hand grabbed me gruffly by the shoulder and pulled me back.

"Now, you think that's impressive," Abby anounced, radiating with joy, just wait for round 2!"

I was shocked. 'We can't be doing this again,' I thought. And either way, I wouldn't be ready for another fifteen minutes, at least. But Hannah plopped some pill in my mouth, and next thing I new, my boner was proudly showing his stuff again. I shrank down to 5'2" tall under the power of the pill, my boner not being as big as usual since I was shorter. That left Abby's whole shoulders over my head, and she was starting to grow with her own exitement again.

"Now, let us show of some of the functions of our product!" Natalie boasted. "It has a fly on mens and womens clothes so that wearers can engage in sex without removing their jackets!"

With that, Abby set her massive frame down on top of mine, her fly and mine unzipped, meeting each other. Without moving, her lips kissed my forehead, and she whispered, "I would normally say I'm sorry, but right now man, I'm so horny, I can't..." she said, and she began thrusting. Finally, I cummed into her again, and she grew on top of me as I shrank. Impressively, my suit still fit like a glove, as did Abby's.

"Now that's more like it!" Abby shouted as she stood her massive body up. Just from the feeling I could tell this was a big one. As I stood up, I realized the full depth of my size change. I was way down to 4' tall, and Abby was huge, at 7'8" tall, due to her slight growth from before I cummed. I felt like a little kid standing next to his mom next to her. Her vagina was at my chin level, and huge legs were as tall as my body minues the head.

"Well folks," Hannah said, "I think you can tell just how well our system works."  I breathed a sigh of relief.

"But just to be sure, lets test it one more time, shall we?!"

The kids in the audience began cheering "One more time! One more time!" I looked pleadingly at Abby, and she stared way down at me in anticipation. Very soon, my boner was back, and I was down to 3'8" tall, now eye-level with her pussy. She grew in anticipation, to 8' tall, leaving me under half of her height. My head was totally under her pussy. This time, she lifted me off the ground, and pressed my miniscule frame against the back wall of the classroom. The kids started shouting "Chug! Chug! Chug!" She began sucking with the most ferocity yet, or maybe it was just how small I was by now. She made quick work of me this time, and held me against the wall as she moved up and I moved down. I went all the way down to 3' tall as she shot up to the positively gargantuan 8'8" tall. Her knee was at my chest level, and my face was in her thigh. Compared to the other girls, I was still small, with their vaginas at my neck level and my face in their belly-buttons. Our suits had held up perfectly, which made me proud, but I was afraid of the day to come. Braced for the worst, I was pleasently surprised when Jessica concluded our presentation. With that, I began walking back to our desk.