Sarah, meanwhile, led by Rat's keen nose had been brought successfully to find more of its kind. Just as she had intended. She'd seen the two slip off, Carmen leading Jorge by the hand while everyone else was milling about gossiping about Kimi.
That's how she found herself peering into the old gym storage closet. A peeping Tom to the incest at play inside.
The twins were in full swing by the time Rat and Sarah began to watch them. Carmen Sat up on a gym horse, bare cheeks on leather. Her top half was still wearing the gym gear of their last class, while on her bottom she only wore socks, the shorts and panties discarded.
Her curly brown hair was tied back into a loose, messy ponytail, with several ringlets having come free, and were plastered to her forehead and sweaty face. Her ears now noticably sticking out from her head, much larger that before, and beginning to turn pink instead of her sallow skin colour.
With both hands she held the hair and hear of an equally curly Jorge, pressing his face into her hungry snatch.
He was kneeling, shorts also around his ankles happily masturbating away while going to town on his sister.
"Ffffuck bro... Hmmmnn. Yeah... Right... Mm. There...". Carmen squeaked, fingers gripping his hair. Her mouth was jawing in silent pleasure in between utterances. The beginning of an overbite just noticeable.
Pushing his head up for the briefest of moments Jorge mumbled, "Fuck, you smell so good lately sis." Before diving back in enthusiastically, making Carmen squeak.
Through the door crack Sarah could smell the musty smell of Carmen's sex, which, she noted, was very similar to Lisa's. As if in agreement Lisa croaked a, "hmmm... Wwrraat". And began to frantically masturbate, shoving a fisted paw into her leaking rat snatch. The smell of Lisa quickly overpowered anything emanating from inside.
Knowing that in the Rat's aura she was safe to do anything sexual, Sarah unclasped her dungarees and let them fall to her ankles before squatting. Slipping a hand under white, damp, panties, she slipped a few fingers into herself and softly moaned, relieved to be finally touching herself.
Back in the room, Jorge's tongue dance into his sister continued as she squealed under him. Ever since Eric and Sarah had lowered inhibitions, the twins had upped their game significantly.
Instead of a few, occasional fumbled explorations born from teenage horny frustration, they had graduated to full on obsession with the others body, and exploring as much of it as possible. Their slow burgeoning changes too, continually made the other more sexually desirable in their growing hyperfixation on each other
Coming up momentarily for air Jorge grunted in satisfaction, Carmen's furry snatch and crotch stared back, slit red and swollen. She's gotten very hairy in the past few weeks. First shaving daily, then, at his insistence, letting it grow out. He didn't know why, but he preferred it that way. So much so he'd convinced her to let her pits grow out too.
"Fuck... Your body is so hot sis", he looked up at her and growled hungrily, "you should take your top off, show me those puffies,"
With only the slightest look of embarrassment, Carmens arms slid to the hem of her sweaty tee, and pulled it gracefully over her head, throwing it to the side.
Sarah's eyes boggled at the next sight. Under the tee, Carmen's bra was very clearly stuffed with some kind of cloth. The girl had always had big tits since puberty, Sarah had seen them bulging out of bras often enough in the locker rooms over the years. But now, no more, just a bra filled with what looked like socks.
She barely had time to process that when a cackling Carmen unclasped the bra and let it fall, revealing her now almost flat chest, sporting only big chewy, pointy, nipples and incredibly puffy areola. The start of her transformation had obviously been to bring her chest in line with that of a rat morph.
"You like my itty bitty puffies bro? Don't miss my milkers?" She cackled.
"Naw sis, these look way hotter on you!", he leaned in and kissed her sex again. "I dunno what's happening to you, but I can't get enough of you." He groaned.
"To us!" She moaned, leaning back and stretching as he dove into her again. And she was right, Sarah could see Jorge's balls were way bigger than normal, not quite Eric sized, but definitely on the way. And he was getting quite hairy on his arms and legs. It still looked within normal human traits, but he definitely was very hairy there.
Coming up for air Jorge grunted, "I don't care Carm, you've never smelled better... You've never made me this horny. Whatever's going on, I like it." He dove in again, this time going for her sweaty rosebud, making Carmen squeak and twitch.
"Ah!!! Fuck yes bro!!! This is fucked, but I feel fucking great! Hnnnghh.. yeah... More there.", one hand twisting her puffy nipples, the other buried in her dripping snatch. Roiling in ecstasy Carmen began twitching, toes curling, as an orgasm swept over her.
Outside, listening in, Sarah had worked herself into an orgasmic frenzy too. More by hearing how much the twins were into their changes so far, it fed the transformative kink in her, and as Carmen squealed a loud orgasm, Sarah grunted and shuddered a silent one in tandem.
Jorge, getting off on the pleasure of his sister grunted his own approval as his cock twitched wildly and began spilling rat seed all over the floor of the storage room.
"Wrrrat. Yummy", the Rat beside Sarah squeaked, eyes bulging and removed its paw from its snatch. Hunching down it made to get into the room cackling, "moooaaaghhhr. Hnngh. Wrratt". In a split second decision Sarah grabbed her sister from behind and scooped her up, holding the wriggling furry creature. She hissed quietly, "Don't you dare... You change more, I'll get the blame. As much as I'd love if you ratted yourself, Eric'd never believe I didn't do it on purpose."
The rat scowled at Sarah and squeaked a pitiful, "wrratt", but stopped wriggling. Sarah scowled back, but then, hearing the twins gather themselves and rustle with clothes she kept a hold of the Rat, quickly fixed herself up and ran.