Fill her on the floor

You approach your mother, cock in hand. “All cleaned up?”

“Mhm,” she mumbles, turning to leave the room.

“Hey, wait. My turn,” you continue, grabbing her wrist. “Don’t you want another dose?”

“I... I guess so. I have been feeling sorta fuzzy, lately.”

“Fuzzy lately” here meaning “dangerously cum-deprived more than a year straight...” But she doesn’t have to know that, you think as you pull her down by the arm. She kneels on the ground without the slightest bit of resistance, her lips just inches from your growing erection.

“Lube it up for me, Mom... You know the drill. Spit, then tongue, then throat.”

“Mmm.” She looks bored as she leans in to lick your shaft, then closes her eyes as she takes you between her huge, pillowy lips.

“Nice and slow, real sloppy—Ungh, there you go,” you coach her, running a hand through her platinum-blonde hair. “You’re a good little cocksucker, aren’t you? Such a good Mommy, taking care of—”

“Mmph—Hey, stop it,” she scolds you, releasing your cockhead only for as long as it takes to say those three words.

“How many times... If you want to drink my jizz, you have to earn it. Be a good Mommy, not a spoiled bitch.”

“Guh? I—Ah!” She cries out as you push her off of your crotch, spit and pre-cum flying from her lips as she topples backward onto the living room floor.

“I want your pussy,” you growl, taking hold of her legs and spreading them high into the air. “Maybe this time I should cum inside, to show you what happens when you aren’t grateful for your medicine?”

“No, I’m sorry, I... Oooh God,” your mother moans as you push your entire spit-slick length inside her. “...I’ll be good, I’ll talk sexy...”

“So do it.”

“F-fuck me, Baby... Ah... Fill me with your b-big, strong cock...” Her performance is fairly convincing, especially given her mental state. She may be a total moron, but she has plenty of practice trying to coax an erection out of you and your brother.

“You want my cum, don’t you?” With each passing second, you pump into her faster. Her pussy clenches around you, and one twitching leg smacks against your back.

“Y-yes I need it—”

“...You want me to fill you up... You want your son to cum inside you...”

She opens her eyes in shock, and you can practically see the gears ticking away inside her

“Ah, um... Is... Is this part of the sexy-talk?”

“Yeah, Mom. Don’t stop now.”

“Oh—Okay, uh... Squirt your seed in me, Marcus... Baby, um... Fill me right up!”

Her acting isn’t quite as good this time around, but just hearing those words is enough to push you over the edge. You drive every inch of your meat into her, then begin to let loose a huge flood of jizz.

“Guuh... Mommy,” you moan, holding onto her fake tits as your hips buck into hers. “...Take my load...”

“Wait, Marcus is this still—”

“Yeeeah... I’m just pretending, Mom... Kiss me.”

As the last ripples of your orgasm pass, she shrugs, closes her eyes, and purses her lips. Just before you can lean into the kiss, though, you notice movement in the corner of your eye.

Your father is standing in the doorway, now fully-dressed with his briefcase in hand. The other hand is wrapped around his cock, stroking it rapidly as he watches you cum inside his wife.

You can’t help but let out a short, delirious chuckle, letting your head fall between your mother’s tits. That gets her attention, and she follows your gaze to the door.

“What—Oh my God, what are you doing? Are you jerking off?”

“Huh?” Your dad is caught by surprise, as though he’s waking up from a trance. He quickly moves to stuff his dick back into his dress pants. “Um... I just...”

“In front of our son—”

“He was fucking you, and—I just thought—”

“This is a medical, um... Thingy,” your mother says, managing to look stern even with you nestled between her legs and breasts. “If you’re going to be gross, then you shouldn’t even be in the room!”

“Fine,” Dad snaps back. He’s usually a beaten-down, mild-mannered guy, but even he sometimes he gets tired of being told off by an unfaithful wife with a rock-bottom-IQ. “I’m going to work. Have fun being a glorified fleshlight.”

“Wait, what’s a flesh—” She’s cut off as he slams the door. Shortly after, you hear his car start... But you barely notice as you begin playfully motor-boating Mom.

“Hey! Cut that out,” she says, although her voice is gentler than when she snapped at your father. “You should pump my mouth now, right Sweetie?”

“Uh... Sorry, but seeing Dad like that really killed the mood,” you lie, pulling your spent cock out. “I gueeess you can try blowing me for a minute, though... Maybe I’ll recover?”

You let Mom suckle your member until it’s clean, but once that’s done you pull it away with an apologetic look. She sighs as you stand up and stretch, oggling her naked body.

She just lies there for a moment, staring vacantly at the wall. When you offer a hand to help her to her feet, she jumps a little and shakes her head.

"S-sorry, I guess I spaced out." Mom rises to her feet and gives you a weak smile, ignoring the puddle of cum she was leaking onto the carpet. After a moment, though, she frowns: “I... I just really really think I need more..."

“Try not to ‘think’ too much, Mommy. You’ll use up all the brain-fuel Cassidy gave you.”

“Okay, but, um... Isn’t there a way I could help you and your brother gimme more medi... Medicum? Or... Or...” She looks away, blushing. “...Maybe I could get a dose somewhere else? If that’s okay.” She looks at you desperately. “Please, Baby. Help me figure it out.”