Toriel

Humans banished the Monster race deep underground. This is irrelevant to Toriel, who prefers to stay inside anyway. Her room was basically her entire home and she never leaves for almost any reason. The very thought of stepping outdoors to do something as simple as pick up things she orders from the nearby Spider Bake Sale causes her to physically recoil. Such a process can take her hours to complete, most of that time spent in her own negative delusions. Yes, staying inside with her beloved games and eroge was the best.

Right now, she was browsing her favorite online imageboard, Ishichan. She enjoyed posting whatever the hell she wanted, which were usually completely unhinged conspiracy theories. In fact, she couldn't remember when this all started, but she was pretty sure a conspiracy she read online about all of Monsterkind having been turned that way by humans was what made her begin living her hikikomori lifestyle to begin with. She'd garnered quite the reputation for the sheer level of vitriol with which she responds to any sort of negativity directed her way, something she convinced herself was something to take pride in. Her online handle was Niitorare which she christened all her posts with.

"F-fuckin' ass-munching fags," she spat while typing her latest hate-filled message to an anon milking her like the lolcow she is, "got no GF, n-no job, no l-life so they h8 on me. Fuckin' w-waste of sperm cells and 9 m-months... Grrr, I'm so mad, gonna g-go have sex with my BF so I won't be so mad, guhuhu~." She snickered to herself, filling her filthy trash-filled room with her voice that was unnaturally uneven for her age. She switched tabs from Ishichan to the new eroge she'd just bought. How she made money was unclear— it certainly wasn't from any kind of job.

"Yes, FINALLY! 'R-Ruin no Shoujou', something with a buttfuck ton of anus-splitting t-tentacles and b-borderline illegal shit!! My raunchy, c-crusty ol' kitty's so wet th-thinking about it already, guhuhu~ n-needa have myself a nice, looong ladyfap riiiite fuckin' nao..." As soon as she got the game booted up on her PC, she opened Cheat Engine and unlocked the game's 100% gallery. Toriel was such a gooner she couldn't even read an eroge on her own when she was horny, something which happened constantly. She never goes a few hours without masturbating on a less-heavy day (not that she could ever tell the difference between night or day).

Immediately she pulls up the CG gallery, searching for the pic that most strikes her fancy. She finds a particularly extreme image— one with a girl of questionable age, bound with scratches all over her body, crying profusely, her eyes wide with shock as the main character rapes her vaginally. At the same time, a tentacle is twisting around in her butthole so harshly that poop is uncontrollably falling out of her prolapsed rectum. Toriel's leg is thumping just looking at it— a sign that this was the one. She squats on her beefy, beat-up gaming chair and reaches for a ridged dildo that came with the eroge's limited edition purchase. She wastes no time bringing the coiled tip of it to her oozing entrance, eager to scratch the itch she's never once allowed to fester since she discovered the act of self-pleasure.

"Aww yeah, p-prime schlicking position. I'm gonna wh-whisk my insides with this t-tenta-cock and with any luck I'll excavate the r-rest of my worthless eggs with this th-thing." She chuckles at her own fucked-up joke, reveling in her penchant for utter depravity. She then jabs the slimy sex toy right in her musky, damp hole, plugging it up with a nasty splurting noise. "Uuunghuuuhhh~!!!" Her face contorts into something probably really grotesque, lifting her shirts that didn't fit her size over her huge mammaries, allowing them to spill forth before immediately pinching them with her free hand.

"Oooh, fuck yesss, Tageru-kuuuunnnn~!! Use your tentacle powers on meeee~!! Fuck, fuck!!" She coos the name of the protagonist whose name she learned from the blurb of her physical copy of Ruin no Shoujou, imagining herself in the girl in the CG's position. "Nngh, that's right! Pound me!! Not that fuckin' SLUT who doesn't deserve your godly dekachin!!" Her free hand then swipes her trusty plastic human dildo which she brings to her asshole, ensuring it doesn't get lonely. "Gwwuuuhhh~ th-that's the wrong h-hole, yanno, guhuhu~ b-but it's okay... T-Tori will be a g-good slut and t-take it all for y-you... Tori's s-slutty fat h-hag body is a-all yours, st-stud...!!"

Thus, Toriel began her sweaty self-love session in her own little paradise, losing herself in her own world and forgetting about the world around her... but of course, life always finds a way to make itself known, and it only ever took the most minor thing to send her fragile mood crashing.