Fandom: Futurama. Idea: Sex in the event that the characters all stayed on Yivo, the endrich being/god that fell in love with the entire universe. Contains: oral, anal, possible impregnation, and incase you couldn't guess, tentacles. Also I'll be referring to Yivo as it because fuck Futurama's made up gender names.
Leela sat back and relaxed in the hot, bubbling water of a spring Yivo had made just for her. She laid with her eyes closed, just enjoying the semi-silence and peace and warmth. Her hands began to move along her body towards her crotch as she considered enjoying the moment alone, but her hands stopped when the knowledge that she wasn't alone, and never could be, returned to her. It was the one thing she still couldn't like about the situation, there was no more alone time. Yivo promised to be silent and not bother her when she asked, but it was still there, still aware of her.
And just like that the moment was ruined, not just for her self pleasure either. Yivo could see her, and she suddenly felt the need to cover herself so the being wasn't ogling her naked form. "Leela, it's alright," Yivo spoke to her, "If you want to touch yourself, if you need release, you don't have to worry. Just go for it, no need to hide or limit anything here. It isn't like the rest of the universe isn't doing the same thing somewhere on me."
"So you just watch as everyone has sex and masturbates?" Leela questioned, trying to decide how disturbing she found this. She supposed it didn't really have a choice, being omnipresent meant Yivo would be watching even if it didn't want to, but still. "Well, no," Yivo said, "Almost everyone else is fine with me joining them for it, and those that I don't play with I only avoid touching because they're exhibionist, and my watching is the greatest pleasure for them."
The knowledge that she was the only being in the universe who didn't feel comfortable being sexual involved with Yivo was a troubling one. Part of her brain wanted to fight for her dignity and believe that it was because Yivo had already technically mated with everyone, and there was still some small confrontational part of her that wanted to believe that the being was still controlling the others, but she knew the truth. She was just stubborn and nervous and frankly, being irrational. The thought of starting with Yivo, truly starting, was a frightening one, as it could literally lead to absolutely anything.
But Leela decided in that moment that if she was destined to be stubborn, the least she could do was focus it on something else. "Yivo," She said after a long pause as she puzzled this out for herself, "I would like you to fuck me." "Ae you sure?" Yivo asked, "I didn't mean to pressure you at all, maybe I shouldn't have mentioned how all the others are with it." Yivo said. Its being afraid that Leela was only doing this out of peer pressure only reaffirmed Leela, and she shook her head, "No, I want to do this, really. Come on, show me how well you're fucking the whole world~" She purred seductively.
The terrain around Leela shuddered, Yivo's arousal by Leela evident. Several tendrils rose from the cloud like ground. They were pink, but lighter than the tendrils that Yivo used to fight, mate, and speak through. These were meant exclusively for pleasure. Leela, in spite of herself, gulped nervously at the sight of them. 'No,' She thought, 'I'm not letting myself be the weakest and shyest being in the universe. I refuse!'
Leela reached out, grabbing the nearest tentacle and squeezing it in her hands. She heard Yivo moan as she did so, pleasured by the pressure. She worked both hands along it, then brought it to her lips as she spread her legs for the others. Yivo wasted no time, thrusting the tentacle into her mouth and letting her suck on it, finding the taste to be rather enjoyable, as was the pleasure as two more of the tendrils pushed into her pussy and ass, moving slowly at first.
Leela could tell that Yivo was holding back for her own sake, not wanting to scare her off with all it could do to her if it wanted to. But Leela wanted it to. Taking the brunt of it, Leela felt, was the only way to make it okay. Leela took the tendril out of her mouth to say, "That all you've got Yivo~? Afraid you won't be able to really stuff me?" She teased.
Yivo didn't miss a bit, immediately forcing the tentacle back into Leela's mouth and into her throat, four more joining it and six joined the tentacles already in her ass and pussy, stretching the holes out as Yivo fucked them. All three sets of tentacles wriggled and pulsed inside of Leela's three holes, making her body writhe in pleasure as she was brutally fucked from every angle. Another tendril began to tease her clit, several wrapping around her to grope her tits and pleasure her nipples.
Leela came hard in a few minutes, and Yivo didn't stop for a second. Leela began to lose track of time after her fourth climax, which was roughly the time Yivo came, unloading a massive amount of thick, hot seed from every tendril, completely covering Leela in it. As Leela's stomch inflated from the amount of cum filling her ass and pussy, not to mention the amount she'd swallowed, Yivo began to put her down, feeling she'd had enough for now, but Yivo stopped her, "Did I say I was done?" She questioned, "I'm just getting started~"
Much like the Rick and Unity story idea, because of the sheer amount of people involved in it (all of organic life in the universe, and an omnipresent being), there really isn't that much of a limit to this idea. It could be one massive one-shot, or a chaptered story with each chapter following a different character/group of characters as they enjoy their being on/with Yivo. Basically every kink is possible here. I only decided to go with Leela here because of her arc during the movie, going from mating Yivo's very existence to loving an accepting it with all the others.