You change your mind! Try to help her

You continue sitting on the toilet, dribbles of semen still escaping your slit while you somewhat awkwardly stare at your best friend's hairless lady bits. It takes you another moment before you tear your vision off her private parts and look back up. "Yeah, yeah, relax," you interrupt her complains. "It's all fine! Did you really forget everything that happened? We talked about it, how you need to pretend being in a relationship with your brother! You know, so that everybody keeps believing that he's simply your boyfriend! If anyone would figure out that he's your brother and tell your parents about it, you'd be grounded till college!" She slowly nods along, as if she's vaguely remembering some things. "As part of that, you ended up having sex with him a couple times. But the other woman, during the party, ended up putting some spermicide into your vag so that you can't get pregnant by accident. All right? And then... well... you ended up having sex all night long. Lots of orgasms for both of you, so I figure it was pretty fun? And because of the spermicide, there's no chance you could get knocked up by big bro." A red blush forms on her cheeks, she's remembering more of what happened. Enough to confirm the story, anyway.

"Oh, wow... I guess... yeah... that's a lot to accept. I'm not a virgin anymore, huh... so I guess I might as well keep up the pretense, then...?" She seemed unsure of the idea of having sex again, but it was tough to tell if that's because she was raised to be a good Christian girl, or if she wasn't fond of the idea to bend over for her own brother, one she admittedly didn't even like all that much! Either it's one of those, or she simply wasn't happy about helping you to get into a relationship with Ryan. Maybe she's jealous! That just makes her deserve an unwanted pregnancy even more, if she's that petty!

On the other hand, now that you look at her, she did look very distressed. And she's your childhood friend, you two go waaaay back! "Listen, uhmm..." you quickly grab some toilet paper to wipe the remaining cum off your crotch, and then get up to investigate what else you may find in the medicine cabinet. There's gotta be something useful still in there. Just got to look around a bit more, aaaand...

"There! If you want to be really sure that nothing goes wrong, you can use these condoms," you point out while handing her a small stack of rubbers, each one with an awkward cartoon drawing of a hairy dick on its packaging. "There's still lots and lots of spermicide inside you anyway, but if you also double-up and wrap up, there's zero risk for you! Just make sure he puts on a new one each time he wants to have sex. Don't let him get close to your private bits until he accepts that!"
This might just ruin your chances with Ryan, but as you try to imagine her face every morning in the near future when she storms to the bathroom to throw up just because she's got her brother's baby growing in her belly... it was hot, but you couldn't do that to her. It's a shame, since it was kind of sexy to see her brother's sperm freely oozing out of her unprotected vagina.

"I don't know about that... what if the condom breaks? Isn't there still a risk?" Looks like you worried needlessly, she's even more afraid of getting knocked up than you are, which is ironic after she was the one who recklessly used up almost an entire container of spermicide just a day ago... man, so much effort just to avoid getting pregnant. Being a girl is tough work!

You turn back around and have another quick look into the medicine cabinet, anything to try and convince her that she's safe and sound. There! "Sit down on the toilet," you instruct her, and she reluctantly steps away from the door to follow your guidance. You retrieve a small digital pen from the cabinet, and approach your friend with it before holding it still in the empty space just between her twat and the toilet. "Okay! Now pee on it," you continue instructing her.

"Do what!? Eww. What kind of pervert are you? That's gross!" she squirms and tries to close her legs, but you keep the stick in place. It's not like you enjoyed this any more than she did!

"It's an ovulation test, silly! Pee on it already!" After hesitating once more, she parts her legs again and attempts to relax. A few splatters of urine hit the stick, enough for the screen to begin blinking anyway. You hold it back up for both of you to see the small display screen turning into a bright red colour. "See? Red means you aren't even fertile... unable to make a baby. You can't get pregnant, okay?" It was a lie and not even a good one, but she didn't know that.

She nods back at you, briefly glimpsing at the bright redness before shrugging her shoulders. "Fine, I guess." Clearly nervous and anxious, she gets back up and unlocks the bathroom door. "Good night then I guess," she adds before closing the door behind herself.

In the meantime, you look back at the small screen while it's still processing and calculating the results until the screen turns a bright pink perhaps a minute or two later.

Ovulation detected! 2-4 eggs!

You press the tiny button located next to the screen to skip to the next message, if Janny comes back this sure as heck isn't something she should see.

Sperm-friendly mucus! Increased chance to conceive!

Again you press the button, trying to deactivate the stupid device! Too much info!

Repeated sexual intercourse for best results!

Another push of the button finally turns the screen blank again! That was so totally and absolutely awkward. Way more information about your friend's genitals than you ever needed to know. It's not like the thing told you any news either, you already knew that your cycles are synced up and that her oven is ready for baby-making. While holding the device with two of your petite fingers, you briefly hold it under running water before putting it back in place. As you do, you also see a package of Morning-After pills in the midst of all that medicine stuff! Great! ... then again, that's some serious chemical stuff. If she ends up taking one just because of some paranoia, she's going to mess up her hormones real good. You walk back over to the toilet with the package in hand, and carefully push one pill after another out of the small tray and right into the toilet's swirling pool of sperm and urine before flushing all of it away and out of sight. The loud sound of sloshing water briefly overshadows everything else, and you continue peering into the bowl for another moment before the sound begins fading... and is replaced by another. Voices, nearby. Sounds like Janny?

Wasn't much of a voice, more like groaning really. You peek out of the bathroom and see that their door was already locked. The rapid squeaking of their bed was freely announcing that their lovemaking was already in progress! The sounds of discomfort however are soon interrupted by a few girly giggles here and there, what the heck were they doing? Did he smack the last bit of sense out of her? Whatever. You decide to check out the master bedroom next and see that Ryan was already asleep under the cozy blanket.

You can also see your phone on the nightstand and it's vibrating and blinking? Upon picking it up, you see a message from Janny... ? It was sent just a minute ago! Judging by the sounds you could still hear through the paper-thin walls, they were anything but done just yet. You tap the screen and maximize the message. I almost forgot how good it feels to have sex! omg! All right then. Pervert.

Her sweet young voice gradually hits a higher and higher pitch, until she releases another perverted moan, drawn-out and so full of bliss and lust that it sounded like a shrieking banshee came for a visit! Holy heck, it baffles your mind how compatible they are! Sex shouldn't feel so good for them! They are brother and sister for christ's sake!

The bed's wooden frame begins creaking more rapidly now, and you breathe a sigh of relief upon realizing they'll soon be done. You can hear Chris grunting like an animal during his sudden release, emptying every last drop of his incestuous seed into the condom, just a tiny barrier to separate his gooey cum from his sibling's fertile vagina. It was stupid how careless they were, but on the other hand, you would've had hell to pay if you had told Janny the truth about how the rubber is her only protection. It may even ruin your entire friendship if she had found out that you stuck a whole bunch of tissues into her hoo-ha just to soak up every last drop of the sperm-killing fluid. In theory, they had around a dozen or so condoms available. It should be enough to keep them covered even if he magically again has the endurance to have intercourse more than once with her.

You turn around and get more comfortable on the bed, now that you've got a chance to sleep. Tomorrow morning you should probably start the day off by collecting your own clothes and your friend's so both of you can get dressed and walk back home. A shower is probably a good idea too, your thighs were a little... crusty. Maybe prepare some breakfast if you have any time to spare.

Just as you close your eyes, you can hear them arguing in the other room. "No, gimme back!" you can hear your best friend arguing. "No no, don't send it to her!" - "Stop!" - "Jerk!"

Your phone vibrates again, and you check to see there's a new message in snapchat. It's marked to be a picture rather than a message, odd.

Sliding your fingertip down to the small notification window, you tap and enlarge it.

The screen of your phone is so bright that your eyes need a moment to readjust from the darkness of your bedroom.

You narrow your eyes to get a better look...

...

Hold on. You can clearly recognize your best friend's bald vagina in its red and puffy glory. Heh, you even chuckle briefly, knowing that she will permanently remain perfectly hairless down there.. and the way she was cutely trying to hide her breasts from the camera. But what's the white... ohhh. Bareback princess... ? WHAT!? NO! Idiot!! That's the opposite of what she was supposed to do! She took his entire load into her cunt! You quickly start tapping the screen to type a message back to her.

TonyStarkFan: Where's the condom I gave you??
JayJay: lol i accidentally told him about the spermicide and then he said its better without condom anywayz
Jayjay: sry but his dick feels nicer without stupid latex XD u know what im talkin about
TonyStarkFan: I told you to be extra careful!
Jayjay: g2g! he wants to set a new record 2nite LOL im down for it

There's the familiar giggling again, and you can hear their bed squeaking in disapproval as soon as Chris began re-positioning his sister to push back into her freshly inseminated twat. What happened to her paranoia!? Was a single climax already enough to completely erase her inhibitions? This time around you knew for sure that his erection was completely uncovered and unprotected, exactly like his sibling's dripping wet pussy. The giggling teenagers didn't take even a single precaution! Billions of his angry sperms were probably already swarming her stupid cervix!

Janny however knew none of that, she released a slutty but pleased moan when he pushed back inside her body. Her silky cunt-flesh instantly wrapped around his dick while he started fucking her hard and deep, probably pushing his previous deposit of seed even further inwards and against the far back of her pussy. It only took a few more thrusts of his before she started moaning out more loudly and encouragingly. Bareback princess. Janny's first all-natural breeding...

Can't say you didn't try to help. You pull the pillow over your head to try and deafen the noise for the next few hours while those two get busy making babies...

zZz...

... that was the plan at least... as soon as you closed your eyes, a set of hands grabbed your waist and rolled you onto your side. "Hot, right?" Ryan spoke with a tired but aroused tone, stupid Janny managed to wake him up with all that moaning...

"AHhnnn!" You gasp and cry out! Something thick just split the lips of your cunt open and began stretching your insides at a rapid pace!

"Told ya, should've tried to keep things wet down there. Hold on, lemme just, hnnn..." he gave you another sudden push and buried his dick entirely in your loins, his heavy testicles resting on the insides of your thigh. Shit, shit, shit! Too big! And you hadn't been nearly turned on enough to handle his size again. You make a mental note to squirt some lube into yourself preemptively for any future encounters. Uncreative as always, he begins pushing into you from behind at the same pace that your best friend was getting fucked, it didn't even matter that you were quiet since her whorish gasps and moans were enough to fuel Ryan's lust! Your perky tits bounced lightly in tune to his thrusting, and all you can think of is how you should've worn a bra to bed...

It only took a minute or so before you started feeling sore, the lack of lubrication didn't help much, thankfully there was enough friction to help Ryan along with his own orgasm. His fingers buried painfully tightly into your skin, and he groaned into your ear. A faint twitching inside your belly served as signal that much like Janny, you were also getting inseminated right then and there. At least you had been smart enough to take care of protection before having sex...

Ryan gently rolled you onto your belly and kept himself on top of you, his flaccid dick stuck inside your twat while both of you drifted off to sleep from exhaustion... with the fading noise of sex still lingering in the distance...