Written by anon, this is just a repost.

Emily hurriedly slipped into the small bathroom, thankfully not drawing any attention in the process. She'd been extra horny as of late, and it certainly showed. While she normally had a just above average sized cock and balls, she had a medical anomaly that caused her modest package to grow every time she orgasmed. Not only that, but her cum production would ramp up as well. While everything would slowly go back to normal with time, she often had a very difficult time not touching herself. But now, things were getting a bit out of hand.
She was busy studying at her college library when her mind started to wander. Fantasies about having a massive cock, so big that sex would be entirely out of the question, with huge, swaying balls that nearly touched the floor when she was standing. She wondered just how much cum she'd make with just one orgasm, probably more than ten average men would in their entire lives.
It wasn't long at all until she felt her girl dick start to stiffen. Her normally six and a half inch long girl dick was currently a monstrous sixteen inches long at full mast, and as thick as her fist. Not only that, but both of her testicles were larger than a baseball, encased in her saggy scrotum. She'd abandoned wearing pants until she could gain enough self control to shrink back down, but even the loose, long skirt she was wearing was just barely able to mask the fact that she had an anaconda between her legs. If it grew any larger she'd have to find some other solution. Even knowing this, she couldn't bring herself to stop.
A side effect of living with her condition did make her quite creative in hiding herself, but she was also a bit on the short side. Her usual tactic of hiding her larger boners by tucking her dick up under her bra wasn't going to cut it at this point, as it'd reach up far enough to be staring her in the face.
She knew she was running out of time.
People would surely notice soon. Not only was her massive cock sticking straight out, pressing against the bottom of the table she was sat at, but there was also small puddle of precum that was starting to grow beneath it. Feeling her thick juices dripping out, along with the pressure from the table, was making her even hornier. She racked her brain for ideas, when one finally came to her.
It had been just a bit chilly that day, so Emily had wore long socks. She glanced around nervously to make sure no one was looking. God, why did it have to be so crowded? When she was certain she wouldn't be spotted, she quickly grasped her cock and stuffed it into her sock.There was still a small gap between sock and skirt where her throbbing member was still visible, but if she was fast she might be lucky enough to not get caught. The fact that she was very shapely would help her case, she couldn't imagine trying to pull something like this off if she had chicken legs
She hastily grabbed her things and stuffed them into her backpack before standing. The feeling of her cock being pressed down on, and encased in the soft fabric, made her need to cum even more dire. After another glance around, she started to powerwalk to the nearest bathroom.
Thankfully, there was a single-person one nearby that she could take some less-traveled routes to; she made it without any incident. If someone did see, they didn't speak up about it. But what happened next filed her with dread.
Occupied. The bathroom was occupied. There was no way she could walk to another one, any other bathroom would put her right in the open, surrounded by people, all able to easily see the thick, fleshy pillar between her legs. The thought of that happening managed to make her hornier, though she wouldn't dare trying to pull a stunt like that. So, she carefully sat down, placed her backpack in front of her, and tried to suppress her sex drive.
It didn't work.
It start with her nervously shifting around, trying to find a position that would attract the least attention. The movements put extra pressure on her cock, and rubbed it against her sock's fabric and on her soft thighs. The sensation made Emily let out a soft moan, and gently rubbed her cock. It oozed precum into her sock, so she removed it to avoid walking around with wet feet. Now that it was out in the open, though, she couldn't look away. Why was this person taking so long to use the bathroom?
Her idle rubbing of her cock was soon joined by her other hand, which gently lifted her large, swollen balls free from her panties. Her package was now fully exposed aside from her vagina, which was completely hidden by her sack. She gently massaged her balls, feeling the pressure building inside them. She'd be in pain soon if she didn't release.
Despite her best efforts to maintain self-control, Emily started to properly beat off in public. Her idle rubbings turned into both hands gripping her stiff erection, stroking it in two places at once. Though her hands were too small to fully wrap around her thick shaft, it still felt heavenly. She let one hand free to start rubbing her engorged pussy lips, which were drooling with cum. To ensure her fluids wouldn't cause a mess, she made sure to rub it all over her cock, balls and pussy, not letting a single drop touch the floor.
In no time at all, the thrill of doing all this in public and the fact that she'd been so aroused for so long combined to make her nearly cum in in only a couple minutes. Knowing that cumming here would be catastrophic, she had no choice but to slow her efforts and try to edge the best she could. 
Finally, after five minutes of Emily playing with herself, she heard the toilet flush. So it wasn't some chick doing her makeup or something, Emily figured. Realizing just how much of a mess her lower half currently was, Emily quickly stuffed her cock back in its home (nearly cumming in the process)
, scooping her balls back into her panties. After hearing the person in the bathroom wash their hands, they stepped out. It was a young woman clad in large headphones, looking to be in her early 20's. She seemed to be red in the face, as if she was straining or something. Maybe she was constipated? Emily waited for her to leave before rising and dashing into the bathroom, closing the door, and yanking down her skirt and panties in one fell swoop. Her balls, glazed with girlcum and musky pre, fell out haphazardly, dropping downwards hard enough to actually hurt a little. Emily stumbled over to the toilet while bending down to free her sword from its sheath. When she made it to the bowl, she grasped her huge cock with both hands and started masturbating in earnest. Precum dripped from her like a leaky faucet, and her balls swayed to and fro as she roughly jacked herself off. She couldn't help but moan quietly, hoping to whatever deity might be out there that no one would be walking by.
That's when the door opened.
Emily froze like a deer in headlights as time seemed to slow. It was the young woman, with her headphones. Emily had nowhere to hide her throbbing dick, so she just released it and awkwardly held her hands back, as if she'd just seen a spider.
"OH! I just, uhm..." The woman started. She was obviously (and rightfully so) shocked at what she was seeing.
"C-can I help you?" Emily said, trying to ignore the very large elephant in the room.
"Yeah, my uh... My bag is over there," she said, pointing next to the toilet. Sure enough, there was a big, leather purse, right in the line of fire for her cock.
"Oh! Well, let me uh.. " Emily trailed off, realizing she couldn't grab this woman's bag with her hands covered in goo. 
"I can get it myself, if you uh, don't mind", the woman said.
"Y-yeah, go ahead..." Emily stammered out, stepping to the side. The woman grabbed her bag, and Emily's cock.
Emily yelped as she felt the strange hand on her dick.
"W-what are you-"
"Sssshhh, I know why you're here, sweetie" the woman said, cutting her off, "let me give you a hand with that."
Emily could not in her wildest dreams imagine anything like this happening, but it was. She could only nod and stare at the woman as she went over to shut and lock the door before placing her hands on the sink, sticking her butt out. She reached back and lifted her skirt, revealing two things that shocked Emily. Firstly, she was wearing no panties. Secondly, the rather large pair of balls and the long, thick, flaccid cock dangling between her legs.
"I was here doing the same thing!" The woman explained. So that's what was taking so long!
"Now, how about you come fuck me?" She said, spreading her very generous ass and revealing her pussy. Since she had just came, it was already wet and ready.
Normally, Emily wouldn't dare do anything even resembling this. She was a virgin, after all, afraid of what people would think of her body. But at this point, the surrealism of it all and the fact that she was more horny than she can recall ever being made her primal instincts take over. 
"That thing is pretty fuckin' big, so take it easy, okay?" The woman said, obviously plenty aroused herself.
Without responding, Emily took her place behind the woman, and pressed her mammoth cock against her pussy. The woman let out a small moan, and gently rubbed her labia on Emily's cock. This sent Emily truly over the edge, and she stuck her cock in straight to the cervix in one fell swoop. The woman let out a yelp as she was suddenly stuffed to the brim with girl meat. Before she could react further, Emily was thrusting in and out of her, but the poor woman could barely even take half of Emily's cock inside her.
"Ooohhhhmmmfffuuuuuck!" she moaned, obviously in ridiculous amounts of pleasure.
Even though Emily was also delighting in the feeling of filling this woman with her dick, she remained almost entirely silent. She had become nothing but a slave to her urges at this point. She had to cum. That was all she could think about. Cumming. Blasting her cum all over the place. Blasting it insi-
Suddenly, with a groan, Emily thrust even deeper. The woman gasped as she felt her cervix being pressed against even harder, fearing she was about to be impaled by the monster inside her. And then she felt Emily cum.
"N-no, d-d..." She couldn't speak. The feeling of being full of both a massive dick and what seemed like a bucket full of cum was just too much. She felt herself tense up before shooting a load of cum herself, splattering the floor.
But Emily's orgasm blew the woman's out of the water. Spurt after massive spurt of cum gushed from her, so much that it was shooting out of the woman's pussy with each shot. It splattered the woman's thighs, and shot out with enough force to actually spray Emily herself. It wasn't until a full minute after that Emily stopped the volley of thick cream shooting out of her. As Emily slowly slid her meat out from the woman, a deluge of spunk burst forth. The woman collapsed to her knees, her pussy leaking out enough of Emily's cum to probably fill up the sink she was leaning against.
But Emily was still hard. And that orgasm was so strong the she'd gained an entire inch of length to her already huge cock. It thickened as well, and she felt her balls swell up. She planned on cumming again, and she'd be using the delirious woman in front of her.