Buffy the Vampire Slayer/Supernatural, Buffy/Mary/John, R, 875 words, originally written for Kink Bingo for the prompt "temperature play".
Just outside of Santa Rosa, the Impala's air conditioning cuts out.
They've got all of the windows open, trying to create some kind of air circulation while they drive, but as John shifts uncomfortably against the leather seat, he can feel the sweat dripping down his back, permeating through the back of his shirt and making his skin stick. He's got a sweating soda can in his hand, but when he finally remembers to take a sip, it's warm and flat, and he chucks it out into the dirt with a grunt of unhappiness.
His gaze moves to the rearview window as a pair of feet come into view, fair and elegant, attached to a pair of legs that seem to go on for miles as they drape over the front seat. Her toes are painted red, but the polish is already chipping. Without a word, he reaches back to tickle them until Mary squeals and shifts in an attempt to get away from them.
"John," she gasps, both a warning and a flirtation, and proceeds to dissolve into giggles alongside her companion in the backseat.
They drive without speaking for a few more minutes, the familiar sounds of Sammy Hagar serenading their less-than-scenic route. The roads are dry, dusty, and John doesn't want to think about how much time he'll have to spend washing out the Impala's insides as well as the outsides as they cross into Nevada.
They've just driven past the state sign, the white letters faded over from orangey dirt, when John overhears the sound of something being opened. There's the crinkling of paper, a small tearing noise, and then a contented sigh, and his eyes immediately snap to the mirror to witness what's going on: Mary, one arm thrown over the backseat, her head pillowed in her hand as she, too, watches the proceedings - the blonde beside her's found a Popsicle that, miraculously, hasn't melted yet. Cherry, from the looks of it, and she's in the process of doing some pretty obscene things to it with that mouth of hers.
John's eyes meet Mary's in the mirror, and he finds himself smirking as he turns up the radio.
They'd picked up Buffy somewhere in California after getting a tip that she was the one to have on the job when dealing with vampires. A successful takedown of a nest had somehow led to the three of them hitting the road together. Two months had turned into three, than five. It's bordering on eight months now, and she is showing no signs of heading back.
And they aren't showing any signs of letting her.
Buffy passes the Popsicle over to Mary, who sticks it in her mouth without any hesitation, sucking on the thing like it's something she's been waiting to do all day, and John shifts in the front again, nudging the gas pedal just a little more with his foot. It's like this for a few more minutes: the two of them, passing the sticky frozen treat back and forth, and the one who doesn't have it in her mouth is sucking on her fingers to get off the remnants, and between the two of them, John's jeans are starting to feel more than slightly snug. He grips the steering wheel when Mary gasps again - only this time, he knows it's a whole different kind, what that kind of sound means when it's coming out of her mouth.
He looks back again and almost slams on the brakes in surprise. Mary's splayed against the backseat, one leg still draped over the front, her shorts sliding down her hips to make room for Buffy's hand, and John watches, mesmerized as Buffy presses two red fingers inside her. Mary's the one with the Popsicle, which somehow, has kept its overall shape, and as the tip disappears into her mouth, John groans.
The Impala swerves over onto the side of the road before he even realizes he's turned the wheel, and he's barely got it stopped in park. It sways and shudders as he turns around to watch, watch the look on Mary's face as Buffy does something with her wrist, her palm pressing against the swell of Mary's belly. Her movements quicken, and Mary's hips jerk lazily, her thighs sticking and unpeeling from the hot leather seat as she surges against Buffy's hand: up, up, up and down, and when she comes, the Popsicle's still in her mouth as she jerks, biting the softened tip off with her teeth.
Buffy withdraws her hand, even does the considerate thing and refastens Mary's shorts, resting her palm against the already-growing bump that protrudes just over the denim. They share a glance, then, the kind they've developed over these past few months that they only reserve for each other, and John's content to watch them then, as Mary briefly rests her head on Buffy's shoulder and her hand joins Buffy's on top of her stomach.
John can't get the grin off his face as they both turn towards him, and Buffy leans in and kisses him, warm tongue inside chilled lips, and eventually, he comes to Mary's cold mouth on his cock and the taste of cherries.