Off the top of my head here are some freeuse plots that may work:
"Narcissistic Nanny." Your super hot au pair is perfecting willing...as long as she can keep using her phone while you fuck her. She scrolls Insta while blowing. Snaps selfies while in cowgirl. Watches tubes in pronebone. In the end you spooge on her phone...thats when she finally acknowledges you with a glare.
"Crossing Lines." You enjoy teasing your voluptuous new stepmom. You especially enjoy her embarrassed reactions when you cross the line over into "inappropriate behavior". Stepmom decides that the best way forward is to avoid encouraging you, so she just ignores you no matter what you do. What starts at grab ass, escalates to fondling knockers, motorboating cleavage, walking in on showers, standing doggie in the kitchen, and so on. Maybe stepmom has an inner monologue where she's like "I can't believe this brat stuck his cock in my mouth. Well I'm not going to give him the satisfaction of seeing me freak out, so I'll just let him facefuck me for a bit."
"Sex Ed Study Session." You're assigned to a study group for your sex ed class. You have a total airhead bimbo who just can't grasp the concepts at all. Luckily there's also a know-it-all brainy nerd girl (takes off glasses...BOOM!). The girls are more consumed with the education aspect and don't really acknowledge that they're fucking. "This is the penis, these are the testicles. Note how the blood flows into it when it is stroked. This is an example of an "erection." "Many couples enjoy oral sex--which looks like this..." "This is the missionary position. If you don't understand maybe you should try it to see if it helps you understand." "I don't think gagging, cowgirl, or snowballing will be on the test but we can go over it if you want."
"Full Service Housecleaner" She really wants a 5-star review so she lets you do whatever while she continues to clean. You flip up the French Maid skirt and fuck her doggie while she's cleaning the bathtub. She puts groceries away on the lower shelves while blowing you. Folds the laundry in cowgirl. Worries that the bed will need to be remade in missionary and smooths the sheets in pronebone. Doesn't want you making a mess so catches every drop in her mouth.
"There's No Such Thing as a Free Ride." Stepsis wants a ride across town, but you're not having that: "Cash, grass, or ass, no one rides for free." Well, she's broke, not holding, and desperate. She does have plenty of ass so its a freeuse for freeride swap.
"Sex While Gaming." A couple of your female college friends come over to play games for awhile. For absolutely no reason at all, sex gets incorporated into the gaming session. They keep playing and talking shit to each other about the game while taking turns on you. Highlights: You wiping out the enemy stronghold while they both blow you and complement your playing skill. Girl #1 riding reverse cowgirl gets really excited from the game and bounces around like crazy. Girl #2 thinks she can get a higher score so they switch places. Scene ends with a ruined cumshot accompanied by the dying Pac-man sound. LOL, JK. Scene ends with both of them in doggie clicking the controllers while you switch back and forth, then you finish on their asses.
"The Warm Welcum." You're traveling through Europe and end up staying with a friendly family. The father is an excellent host and insists that his wife, stepdaughter(s), mother-in-law, cook, and maid all cater to your every whim. He insists they unpack your belongings. Cook you dinner. Give you a foot rub. And it escalates from there. He really is a very generous host.
"The Hangout" Someone mentioned this JAV-VR scenario above. Here's a westernized version. You live next door to a sorority house and you have an awesome pool. The sorority sisters are welcome to come over and enjoy the pool, but there's catch--one or more of them has to entertain your dick the whole time. So they take turns fulfilling their obligation while the others basically ignore you until its their turn to tag in.