Jen and Claire had been fused in one way or another for the past two days and had grown to love it, so before they left for school they attempted once more to re-merge themselves. They both spit out a pill, split it, and the each ate one half to their pill an one half of the others, hoping to maximize their chances of merging.
Both Jen and Claire's heads moved over to one side as a new head grew in beside them, on Jen's shoulders was a copy of Claire's head, but with a normal mouth and on Claire's shoulders was a copy of Jen's head, with a mouth vagina. Claire then grew a second penis between her original legs, this one with Jen's mouth on the end.
The changes were quick, but they left both sisters disoriented, both of them now seeing from two separate viewpoints. After a bit of experimentation, the two sisters found that while either of them could control either body, the one who originally owned the body had priority.
"Wow, I actually really like this change, we're still separate, but we're also merged!” Jen said through her cock-mouth on Claire's body.
“Yeah, and now we can be in two places at once!” Claire said from her head on Jen's body
The two sisters were horny from the transformation, but before they could do anything, Martha reminded them about school. Jen and Claire wanted to sate their lust right now, but figured that they would have plenty of time to do it while at school once they started giving people pills.
They quickly finished getting ready and left to go to school. Luckily since they had relatively humanoid bodies they were able to ride the bus today. Getting out to the bus was a bit of a struggle for their body with the cock-limbs, but the sisters were soon seated with their bodies across the aisle from each other at the back of the bus. Beside Claire's original body was Leah, a girl that neither girl knew outside of sharing a few classes, and beside Jen's original body was Jake, a boy that Claire had a crush on a few years ago but she hadn't acted upon it and got over him soon after.
The two sisters were still horny from their earlier transformations and needed to get some relief soon. They silently deiced that the two people beside them would be the targets of the pills. As the bus made it's way to school Jen and Claire were waiting for an opportunity to give a pill to Leah and Jake. Eventually an opportunity presented itself for Leah when she pulled out a bag of trail mix and began to snack from it as she continued to gaze out the window, giving the girls a perfect opportunity to drop a pill into the bag.
When Leah ate her next handful of trail mix her mouth sealed up, with a cock and balls growing in it's place. Her ears then moved to the top of hear head and morphed into pointed cat ears, while a pair of feline tails grew out of her back. Her shirt and bra vanished as another pair of breasts grew in beneath her originals and all four of her nipples turned into mouths, which she then continued eating her trail mix with.
“Hey Jen, Claire I'm feeling kinda horny right now, wanna fuck?” The cat-girl asked with one of her lipples while another one chewed her snack.
Jen and Claire eagerly nodded the heads of Claire's body, turning towards Leah. The cat-girl swallowed her snack before she hugged the sisters tight, her bottom pair of lipples engulfing their dick-nipples while her top pair begin to eat out their vagina-nipples. Leah then stuck her cock-mouth into Claire's vagina-mouth in a strange kind of kiss.
One of their bodies getting action only makes Jen and Claire more desperate to get their other body some as well, so in a lustful fir, Jen wraps clumsily used one of her cock arms to pull Jake into a kiss and spits a pill down his throat.
The boy looks at the two in confusion for a moment after Jen breaks the kiss, but as soon as his changes begin the look is replace by one of intense lust. His hair thickened into a nest of dozens of snakes. His tongue fell out of his mouth, revealing it was now a two-headed snake. His arms then morphed into two long and thick snakes as well. His legs fused into a snake-tail that grew underneath the seat in front of them, his clothes fading away as it did so. His nipples then grew into short snakes, before his pecs ballooned into a large pair of breasts. The rest of his body then rapidly feminized, with his, now her, cock receding into a cloacal slit below where her torso transitions into her tail. Her slit then opened back up revealing a snake-like vagina as well as a pair of three foot long snake-cocks.
Once her transformation finished the snaky lamia wrapped her snake-arms around the sisters cock-arms and began to stroke them. She then coiled her snake cocks together and used them to fuck their vagina. Jen pulled Jake back into their kiss, sucking on the lamia's snake tongue as her snake-nipples licked the sisters normal nipples.
By the time the bus arrived at school the four lovers had satisfied themselves, Leah and Jake going off to their classes as Jen and Claire check their schedule to see how their classes work with their shared bodies.