Tammy takes the underwear first, which happens to be a jock strap size XXXL.
She had never really seen one this close before. She reached under her skirt and pulled off her panties. At first she doesn't know how to put it on. Something was guiding her as she automatically stepped into it. As she pulled it up her legs the straps felt like they were getting smaller,so she thought. Her once small hips expanded a few sizes larger for a female but just the right size for a male. She was surprised see that it fit so snugly around her waist and upper legs. Even though the leg straps pulled the bottom of the pouch tightly between her legs the rest of the pouch hung vacant with nothing to hold.
Tammy felt a strange sensation in her crotch. It felt like something was growing down there. She reach down to feel the front of the pouch. It felt like someone was blowing up a toy balloon down there. With ever passing moment the "balloon" got bigger and bigger. Tammy pulled off her skirt so she could see the pouch growing. It looked like she had stuffed a large banana and two small oranges down there.
Soon the pouch was filled to its limit. The weight pulling down the top of the pouch until golden patch of groin hair could be seen leading up to her abs.
Next Jill handed Tammy a pair of leather pants. Tammy sat down on a nearby stool so she could put on the pants. She had a difficult time adjusting the bulge the jock strap created. But when she stuffed it into the pants she found ample room to zip up the zipper As she readjusted her bulge the pants started to shrink wrap themselves around her smaller legs.
Soon the once smaller female legs started to grow larger. The growth started with the calves. They grew to three time their former size. Her thighs grew until their combined mass made the bulge of her groin stick out more obscenely than ever. Her once perky female ass shrank to a rock hard striated male ass.
The last to change was her face. Her blond hair receded back into scalp until it was a high and tight crew cut. Her face grew more rugged as a trimmed goatee formed on her lower face. Tammy was now Thomas.