Amber went off to the shower to begin her ritual cleaning while Elisabeth sat with her brother in his bedroom as he changed into his swim trunks. Nick was nervous, with his sister's eyes on him like that, and despite getting off twice in the last fifteen minutes, first by getting his first blowjob from Amber and then just from seeing his sister eat his cum out of Amber's mouth, his cock swelled to erection again.
"Do you have to stare?" Nick protested, pulling up his trunks in an attempt to hide his bulging erection from his little sister. He succeeded only in making a tent out of his swimsuit.
"Oh, come off it," Elisabeth laughed. "I've already seen your cock and I know you think I'm the sexiest thing on Earth. You don't have it hide it from me anymore."
Nick blushed.
"So... Tell me about this taboo you that Amber violated," Nick said, pulling his drawstring and adjusting his cock in his trunks in a futile attempt to make it fit better.
To Nick's surprise, it was now his sister's turn to blush as she covered her face with her hands to brace herself while she spoke.
"Amber and I took an oath a month ago when we started doing magick," Elisabeth replied nervously. "We're not supposed to have sex with anyone either of us cares about unless the other one is there to participate. It's a bond that's supposed give us a head start with difficult rituals that require two people. Of course, a proper coven is supposed to have three witches, but two is enough for most sex magick."
"Sex magick!" Nick stammered, nearly tripping over himself in his eagerness for information. "You mean you... you... you're having hot kinky lesbian sex with that... That..." he motioned towards the wall that his bedroom shared with the hall bathroom, where Amber was showering. "That sexy creature."
"Amber's my best friend and she's smart, so she was the perfect choice for a partner. I do have to admit, I expected her to have a little more self control."
Nick turned red, remembering how eagerly Amber had pounced on his cock a short while ago, when she caught him alone masturbating. It was so damn hot! But he didn't like that it made Elisabeth angry with Amber.
"What if I join your coven?" Nick asked nervously. "I could be your third witch, assuming men can be witches. Then you could go on with your ritual without having to punish Amber and everything would be ok."
"Nice try," Elisabeth replied, absent-mindedly tugging on her bikini bottoms to make them cling more smoothly to her body. "Amber broke the taboo and that won't be erased so easily." She stepped forward and grabbed Nick by the erection.
Nick gasped. His sister's touch made his cock burn. He wanted to be fucked so badly that it hurt.
"You have some potential, though," Elisabeth whispered seductively in his ear. "And Amber seems to like you. I'll tell you what. Tonight, after you steal Mom's sex toys for me, you can come in and observe me and Amber perform the ritual. If you still want to join us, we'll consider initiating you."
Nick's cock twitched. He was being offered every man's dream. Hot sex with two beautiful women at a time! He nearly erupted in orgasm. And tonight, he'd get to watch the two at them have a go at each other! He could hardly wait.
"Can I watch you punish Amber?" Nick asked, grabbing a towel and wrapping it around his waist. "I feel somewhat responsible."
"Of course," Elisabeth said. "You know enough that we don't have to keep it a secret from you."
"But what will you do to her?" Nick asked, his brotherly instincts running wild. Could he stand by and let Elisabeth do it if it turned out to be something really awful and violent?
"I'd fuck her up the ass with a strap-on, if I had one," Elisabeth replied musingly. "But since I don't, sixty-nine whacks on the ass with a ruler, and then forcing her to go swimming with her bikini stuffed up her pussy sounds like a good idea.
Nick nearly soiled himself. He ran to his desk and pulled out the old ruler he used to hide his used tissues.
"Use this," Nick said in a ragged voice, handing his sister the implement.
Elisabeth accepted it gladly.
"You know what, Nick?" she said, tucking the ruler under the side of her bikini bottoms. "I think you're going to be fun to work with."
She picked up her things and, grabbing Nick by the hand, stepped outside into the sunlight.
Elisabeth set her towel down on the cement near the pool to sun herself while she waited for Amber to join them.
Nick was so nervous that he couldn't sit still, so he dived off the diving board and began swimming laps to burn off some of the anticipation. Any fear he had harbored about Amber's punishment was now replaced with the lucid desire to see something so kinky with his own eyes, and the erection in his swim trunks stubbornly refused to dissipate. It felt like ages before he saw Amber walking to the pool, wearing her little pink bikini. Nick was shockingly aware of her body underneath the material of the swimsuit, as though the bikini acted to emphasize the swell of her breasts and cunt. The way she moved her body was both proud and demure, as though she was bracing herself for some difficult ordeal.
Elisabeth rose from her towel and walked towards her friend, grabbing her by the breast and kissing her briefly on the lips in a sign of greeting. Nick gasped. It was so hot! He pulled himself up out of the pool by the metal ladder and walked over to the couple, who were engaged in a conversation he couldn't hear.