The air was brimming with the sounds of train tracks, slurps, plunges, and feminine moans.
Candice's skin glowed with a fine sheen as her body erotically writhed under Cottonmouth's attention. Her head was brutally pinned, as two feet of cock slithered down her gullet. It wiggled and twisted around, enjoying the taut confines wrapping around it's shaft.
Despite it all, her focus centered on the agitation happening between her legs. By all accounts, this should be a horrid ordeal, with a nightmarish freak ravishing her insides. Instead, she was so aroused, her lower body was bucking with spasms now. The wriggling shank was so wet and firm, licking into every last square inch of her overstimulated tunnel. Even the tip mashed up against her cervix was giving her the feels.
"How could this be?," Candice wondered. She could only imagine the sight from afar, bent over and defiled beyond all reality. And here she was, here and now, edging closer to climax. But then Cottonmouth began to shake, and Candice immediately had the presence of mind to think of the beaker. She needed that sperm sample, and it would do no good buried deep down her esophagus.
"MMmmmmpph"
She mustered all of her remaining strength, pushing at the slight frame of his body. His emaciated pelvis lifted off, disengaging the entirety of his cock out her maw. With the sweet lengthy retreat, the milking action of her mouth and tongue over shaft and glans, spurred the last sensation he needed.
His entire cock felt like one gigantic cramp, drawing out everything from his balls. Candice squealed as spurt after spurt of hot jizz threw out like jabs. What happened next shocked her to the core. Having his manly cum coating her face felt so incredibly submissive, and it pushed her over the edge.
"Ohhhhhhhhhhhhhhhh..."
As Cottonmouth stumbled backwards, Candice arched her back. She's had orgasms before in her inexperienced sex life, from light masturbation to heavy petting from inept boyfriends. But whatever this was, rocked her world like nothing else. It felt like a giant series of fireworks blew her brains out. Her body continued to spasm with one sexy aftershock after another.

After a lengthy recovery period, both bodies were sprawled on the floor, laboring to breathe back to normal.
"h-help us...," he croaked.
"w-what?? how... what can I do?," she managed to breathily mutter back.
"the plugs..."
"what do you mean?"
"the plugs... the plugs...," he replied even softer.
"I-I don't understand."
Candice got up, wondering about this seemingly new clue. Grabbing a beaker from the machine, her nose scrunched at the notion of collecting Cottonmouth's semen. After depositing a copious mouthful of seed, she used her fingers to scrape off the lines of pearly cum off her face into the jar. Of course, it was all so demeaning to smear his stuff, but it was all about escaping at this point.
She replayed his clue over and over in her head, trying to make sense of it. As the door swooshed open, Cottonmouth lifted his head one last time.
"Thanksssssssssssssss..."
Candice gave him one hell of a glare and exited into the night air to the next boxcar.