David suddenly felt a tingling sensation on his chest and he frowned as he looked down, seeing his t-shirt slowly inflating in front with what were obviously a pair of perky breasts... about the same size as his sister's. The feminine flesh pushed out of his chest, and as he felt his nipples grow larger and rub against his t-shirt, David felt his cock twitch in excitement. "David?" Alicia suddenly asked.
"Huh?" David muttered, looking up and over at his sister, who was now missing her boobs, her blouse and black sweater sat missing their usual protrusions. Her bra was now redundant, sat on her flat, very male and slightly hairy chest. He'd actually taken his sister's breasts without meaning to.
"I asked you how college was." Alicia asked, "but you kinda zoned out on me." she chuckled, apparently unaware of her missing C-cups.
David tried to compose himself, but by now he had an erection tenting his boxer shorts and pressing uncomfortably against his jeans. The extra weight on his chest felt weird... but also nice, and his new nipples were as erect as his cock. "Oh, it's fine, no trouble here." he answered vaguely.
"Not struggling with any classes? Really?" Alicia said incredulously.
"What's that supposed to mean? I'm awesome in every class." David defended himself, sticking his tongue out at his sister.
Alicia nodded, feigning agreement. "Yeah, course you are little bro." she smirked. "Anyway, where's the bathroom? I gotta pee!" she then said, looking around. David pointed in the right direction without saying anything, then once his sister had walked out of the room, his hands shot up to his chest to squeeze his new tits, his older sister's tits that is. They felt so nice, and he was tempted to keep them for a while since Alicia didn't notice anything out of the ordinary.
He got that preoccupied with playing with his new breasts, that he didn't hear Alicia come back into the room a few minutes later. "Bro, what are you doing? Are your boobs itching or something?" she asked, startling him.
"Oh... shit, you scared me," David replied, blushing a little as his hands dropped into his lap, "er... my nipples are... um... chafing a little, that's all." he told her.
Alicia smiled. "I can lend you my bra if you like, goodness knows I don't really need it." she offered as she sat down. In this new reality, Alicia was jealous that David and Jamie had both developed breasts while she hadn't.
"Er... no, it's okay, I can put up with it." David smiled, pondering whether to return his sister's breasts to her or not just yet.