Dan stroked his turgid six-incher as he thought about his sister’s friend Madison in the shower across the hall, the warm water rolling down the pear-shaped ash blonde’s naked body. Unlike normally, though, the blond-haired young man was in his sister’s room and wanking into Madison’s underwear. He didn’t know where his sister was, but he knew he wouldn’t be long at all. Sure enough, after only a minute of pleasure, he grunted and filled the gusset of the panties with his voluminous load.

“Got it!”

“BWAHHH!” he yelped, dropped the sodden article, and turned to see his twin sister Hana standing there, pointing her phone’s camera at him. “How ... how long have you been there?!”

The dark-haired girl grinned as she tapped at the screen. “The whole time! You just walked in and started ... y’know...”

Dan’s mind boggled as he tucked his dwindling member back into his jeans. He had definitely confirmed that he was alone when he came in, and again before he pulled his dick out. “You ... but no...”

“‘Dirty Deed complete, Koins earned,’” Hana read from her screen. “Nice.”

He lunged for the phone. “Delete that!”

She pulled the device back, out of his reach. “I wasn’t recording ... the app can register what’s going on through the camera.”

“What app?”

She turned the screen so he could see. There was a stylized, multi-colored K logo, and below it said ‘Dirty Deeds’. “I have to prove to the app that ‘dirty’ stuff happens, then I get Koins that give me bonuses or something. The instructions were a bit unclear, but when you came in and whipped out your dick — nice one, by the way — I figured what the hell.”

“But you definitely weren’t in here ... I double-checked,” Dan whined.

“You looked right at me, dude.”

The door opened and Madison stepped in wearing just a towel. “Oh! Hey, Dan.”

“Uh, hey.”

The 18-year-old blonde once again noticed the vast difference between her friend Hana and her fraternal twin, the likewise 18-year-old Dan being a fit, somewhat cute blond while his slim, short sister was half-Asian with dark hair, the result of an in vitro fertilization treatment gone wrong where their mother’s two eggs got fertilized by the sperm of two different men. “I gotta get dressed, so...”

“Oh, right.” He left and closed the door behind.

Madison turned to the mirror over Hana’s desk to check out her eyebrows before donning her glasses. “Hey, pass me my panties?” She felt a bit wet between her legs after pulling them on, but figured that she’d missed properly drying down there.

Off to the side, Hana smiled as she got more Koins.

Hana slipped into her brother’s room wearing a bikini and an eager grin. “I wanna try something ... you up for it?”

He looked at her phone’s screen. “Normally Nude?” He followed his sister into the back yard where he found Madison lying on a patio lounger in her one-piece swimsuit, soaking up the rays from one of the first warm days of late Spring.

Hana pointed the phone’s camera at her friend and enabled the bonus. A moment later, the blonde got to her feet, pulled off her suit, and lay back as if it was something she’d done many times before.

Dan’s eyes boggled at Madison’s B-cup breasts with their wide, pink areolas. Freshly freed into the slightly cool afternoon air, they hardened as he watched. As if in a trance, he stumbled toward her. Once he came into frame of the phone’s camera, though, he started pulling his own clothes off. He was likewise fully naked by the time he reached their overnight visitor.

“Oh, um...” Hana began, but she quickly shut up, shaking her head that she was seeing her brother’s hard cock for the second time that day.

“Hey, Madison, can I rub lotion on you?” he asked.

The blonde looked up to see Dan’s erection pointing at her, but didn’t even blink. “Oh, yeah, please ... I don’t want to burn.” She turned onto her front.

Dan knelt down and began applying Coppertone along Madison’s pale back, then moved his hands down to her plush bottom. However, he stayed professional while making sure that the lotion got liberally applied to those round globes. She flipped back over and held her hand out for the tube so that she could protect her chest and tummy. “Thanks.”

“No problem!” He headed back to his sister, a big smile on his face.

“What’s going on out here? HOLY--!”

Hana quickly turned to see her mother stepping into the back yard in her gardening outfit of shorts and a button-down shirt tied under her prominent breasts. Her shock at seeing her son and Madison buck naked quickly evaporated as she pulled her own clothes off. “Such a lovely day!” the brown-haired woman commented as she revealed her curvy body to everyone.

“You look beautiful!” Madison called from the lounger.

“You too!” The older woman headed to her garden, trowel in hand.

Once it was obvious that nothing else was going to happen, Hana closed up the app and then everyone re-dressed as if nothing strange had happened.

“You get any Koins for that?” Dan asked her as they went back inside.

She checked her total ... the cost of the Normally Nude feature was offset by the Dirty Deeds it had noted, namely semi-public nudity. “This is crazy! How does it work?” she mused.

“What do you mean, crazy? We were just being nude around each other ... no big deal.”

“So do you want to take off your clothes now?”

“What?! Of course not.” Then he thought for a moment. “Oh, I see. What the heck? Where did you find this app?”

“Woke up this morning and it was just there. I can’t seem to uninstall it, and the instructions were ridiculous, but this is like magic or something, right?”

“Apps are technology, not magic.”

She put a finger on her chin. “Books are technology as well, and according to fantasy stories, there are spell books. Why not spell apps?”

“You just made everyone in the back yard not care that they were naked ... that’s fucking mind control, Hana! That’s too much power for one person.”

“Okay, so I won’t use it unless you agree ... two people. Better?”

He stood there, considering.

“Looks like I have enough points to try something with Mrs. Trainor tomorrow...” she trilled.

“Fuck ... okay, we’ll give it a try.”

She gave him an eager grin.

Mrs. Trainor was a voluptuous, thirtysomething brunette of uncertain heritage, her eyes green but with freckles and a slight tilting of her eyes that indicated some sort of Asian ancestry. She spoke perfect English, though, and taught that class. When the lunch bell rang, the twins stayed behind with the woman.

“Okay, go talk to her,” Hana told him as she pulled out her phone.

“Hey, Mrs. Trainor...”

“Dan! I thought I saw Hana...” She looked around the otherwise empty classroom, her eyes slipping over the other twin standing there with her phone’s camera pointed at them.

Hana selected the bonus: Gush. It would take most of the Koins they’d earned and didn’t have any description. The effect, though, happened quickly.

“Ugh...” Dan groaned and bent over a little.

“Umm...” Mrs. Trainor sat back in her chair, her eyes fluttering. Her hands moved to her blouse-covered, C-cup breasts. However, when she noticed that her student seemed to be in pain, she snapped to attention. “Dan? What’s the matter?”

“Hurts...” The young man adjusted his hard cock in its confining briefs.

“Let ... let me see it,” his teacher helpfully directed him.

He only took a moment to unfasten his jeans and pull them and his underwear down. Both women gasped ... Dan’s cock had to be at least 8 inches long now, and thick! Pearlescent liquid drooled from the tip.

Mrs. T licked her lips. “Oh, you poor boy! Do you want me to ... help?”

“Please ... oh God...” He stroked at it.

The teacher knelt at his feet and took the meaty staff in her hand. Her fingers looked small in comparison, and she felt his pre-cum inundating them. Switching to her other hand, she licked her digits clean. “Mmm...” She moved her good hand down, under her skirt, to find her underwear absolutely soaked with her own juices. It was awkward to stroke the young man with her off hand, so with barely a thought, she took his member into her mouth while she masturbated. After a couple of minutes of this, she had swallowed a good amount of his abundant pre-cum but he still hadn’t orgasmed. Likewise, while her fingers felt good as she sluiced them into her sodden pussy, she couldn’t reach the release that she so desperately needed.

She pulled off with a smack of her lips and maneuvered the young man to lay back on her desk, then quickly pulled off her skirt and panties before climbing astride him. With how saturated her nethers were, she had no problems slotting the purplish head of his penis between the lips of her engorged vulva. “Soo ... biiigg...” she moaned as she took his length inside her married pussy.

Hana beheld all of this through her phone screen. Her brother’s dick was huge, and she could see his balls were likewise swollen. Since neither of the rutting couple seemed to notice her, and remembering that her brother had only registered her presence back in her room when she spoke, she got close and whispered into his ear, “Take off her blouse.”

Dan wasted no time in doing that, revealing his teacher’s black lace bra, her breasts straining at the titsling; they seemed bigger as well. He tried in vain to pull it off, but Mrs. T finally just unfastened it, shrugging both it and her blouse off. Now completely naked, the wanton teacher moved faster upon her student.

“Oh God ... oh God ... oh God...” she moaned, Dan’s thick cock touching her in places that her husband’s had never been able to reach. Just a little more, she knew, and that insistent itch deep inside would finally be scratched.

Dan was surprised that his first time had lasted as long as it had, but he still felt the pressure building up, the discomfort offsetting the pleasure of losing his virginity with the sexy teacher. All of a sudden, however, he felt something give, followed by an explosion of ecstasy from between his legs. Instinctively, he grabbed the woman’s rounded hips and pulled them down as he thrust up. “Hrr ... AHHH!”

“Wait, not insiii...” the older woman started, but then she felt the first burst of the young man’s sperm fill her, the hot blossoming of seed setting off her own orgasm. “ ... iiiii...” Her body froze, holding her in place as the next throb signaled another gush of dangerous cum.

Hana shifted her view to behind the rutting couple to find her brother’s bulbous scrotum pulsating as it released shot after shot of his youthful seed deep inside their teacher.

Mrs. Trainor shook atop her illicit lover. “ ... IIIII...!” Her voice ramped up and suddenly her crotch shot warm liquid up Dan’s stomach as she squirted.

Hana shifted position to catch that and her eyes goggled at the teacher’s midsection as it visibly bulged a little. Was her brother shooting that much inside the woman?

“ ... IIII...” Mrs. T continued, her mouth and eyes wide as a veritable flood of semen jetted into her womb, filling every dark corner of her uterus and Fallopian tubes with dangerous sperm.

Gush! Gush! Gush! Finally, looking like she was already three months pregnant, the older woman gave a gasp and collapsed unconscious onto Dan’s chest.

“Holy fuck...” Dan moaned, his mouth feeling like a desert.

Hana saw several banners appear within the K app: - Teacher/student sex - Unprotected sex - Cheating sex - Potential pregnancy (2x Multiplier)

Her eyes widened as she saw the amount of Koins she now had.

Mrs. Trainor, furiously cleaning her classroom after opening all the windows to air it out, asked Dan to keep what they’d done quiet. She still didn’t notice Hana off to the side with her phone out.

As the twins left the room, Dan turned to his sister. “I can’t believe I got to fuck Mrs. Trainor! That app is amazing!”

She nodded. “New bonuses opened up, and I really want to test them right now.”

“Hana, there’s no way I can get it back up after tha--AAHH!” he cried out as his deflated member roared back to life, though only to his regular six-inch size.

“Heh,” Hana chuckled, “that was ‘Recharge’.” Some students down the hall were eyeing them after Dan’s loud exclamation. “C’mon...” She pulled him toward the nurse’s office.