Before the three of you went to call friends to switch with you ended up leaning against a machine and just looked at your body... well Erin's body. You guessed she would become sexy when older, but currently she was a little small for you. However you couldn't ask too much more or less from a 13 year old. You leaned further down a little as you accidentally pressed a few buttons on the machine and suddenly there was a flash. You slipped and fell down.
Erin said "Careful with my body there! What did yo-... are you feeling alright?"
You said "Yeah I'm alright, You're clothes ju... st... feel a little... tight" You noticed your voice had matured and then you looked to your body. Your clothes looked like they shrank, but really your body just was stretching it out as your now D-cup breasts were tenting out the shirt as if it were a large tight bra, and your short shorts were now more like a thong on your plump bootie and hips.
The machine behind said "transformation complete, you are now 20 years old."
Picking yourself up you said "So now i'm your guys age..." as you stretched up your shirt and shorts snapped leaving you bare naked. You attempted to cover your body as odd feelings started to emerge from your privates.
Harry's bulge started to grow a bit and said "Let's find something to clothe you with then Philip"
You walked towards Harry in your old body and said "...Why not solve a little problem... that age change must've really riled up my hormones..."
Harry said "No, I couldn't have sex with my sister!"
You said "Your not. I'm your friend and currently my brother is Erin. You can have fun in my body. I don't mind."
Erin coughed and said "I don't appreciate you guys talking about having sex with my body like that."
pulling down your body's trousers you asked "So what are you gonna do about it?"
Erin went to the machine you had hit and typed in some things and a flash of light occured. After the flash ended you looked around and saw your body had remained the same, but Harry was now a toddler. The machine said "Transformation complete, you are now 5 years old."
Harry in a puddle of clothes said "Oh Come on! Well two can play that game!" He scurried to a table with a bunch of lazer guns and fired one at Erin.
Erin spasmed a little as his male body started to shrink as his body hair started to withdraw. Then his male organs withdrew and his chest started to grow. Erin changed back into a woman as she saw that her breasts were a C-cup. she said "I was a girl originally you know... this isn't exactly a punishment."
Harry took out a tablet and then said "But this could be." he then tapped a few things and Erin's breasts and butt started to shrink as your breasts expanded further into G-cups and your butt and hips were extraordinarily large.
You said "Come on... I know I may be horny but I want to be able to function normally!"
Erin said "Let's stop this right now and get everything straight... what are we going to do now?"