"I know what I wanna try first," Rebecca said.
"Go on," Ty agreed.
"Turn me into a boy for a bit! I wanna see what it's like."
Ty felt a little twinge of disappointment- he felt like Becca was really hot, though he didn't feel like he could tell her, and couldn't see why she'd want to give up her beautiful body for a male one. But hey, she was his friend, and this would make her happy. "OK, sure!"
Becca saw his expression focus again, and felt a warm tingling overwhelm her. All of a sudden, she felt... stronger. Firmer. More instinctual. Her clothes seemed to tighten and chafe around her, and she said, "Ty, mind if I take these off?" She smirked as he blushed hard, and pulled off her crop top, shucked her skirt, undid and dropped her bra (quietly reflecting on how she wouldn't need one for quite a while, and took her panties off. She felt no shame about Ty seeing her naked right now, considering she wouldn't have this body for much longer.
Ty had assumed he wouldn't want to see this, but instead he found he couldn't take his eyes off Becca's body as it became masculine. Her muscles rippled under her skin and enlarged, her figure going from curvy and petite to straight and firm while her hands and feet also grew. Her jawline firmed and he heard her voice and breathing deepen as a bulge emerged in her throat. Her breasts receded into her chest until it was flat again, inert nipples atop pectorals the only remnant of her mammaries. She began sprouting way more body hair, reminding Ty of a werewolf transformation, until it covered most of her body- she even had some faint stubble on her chin.
Becca grunted in the deep baritone of a young man as his genitalia reshaped. His vagina sealed up, and he pushed two round lumps out of himself which plopped inside it and stretched the skin, while his clitoris protruded and widened until it became a phallus, the tip oozing white precum from his freshly formed testicles.
A name emerged in both their minds- Ryan. Ryan opened his eyes and saw Ty appeared amazed at having seen him change. "How do I look?" he asked, and then laughed, "I mean, I sound pretty good, so that's a good start!" He peered down at himself, and quietly observed his handsome body.
Meanwhile, Ty's jaw was still on the floor, and though Ryan thankfully hadn't noticed, he had a massive throbbing boner. He had assumed he wouldn't find Becca attractive anymore as a man, but he absolutely did. Ryan's firm pecs and muscles, toned body and large cock were making Ty's mind glaze over with arousal- and he wondered what to do about them, or Ryan would make him do something first...