Reptilian Brain

Ethan quickly pulled down his boxers, releasing the Kraken. On Earth, he had a six-inch pecker, which most men would consider average. However, it was nothing to be proud of.

On Promiscua, the eighteen-year-old Cromwell heir was naturally blessed and even received an enhancement through a system reward. The engorgement pill he received brought his full-blown size to ten inches!

However, presently, as the boy held his erect dick in his hand, he realized something was wrong. What was different? Was the shape weird? No! Did it look diseased? Of course not! Wait! It wasn't as enormous as before!

The realization was bizarre since Ethan was very aroused, and his pole couldn't get any harder at this point. What caused the shrinkage?

Did the engorgement pill's effects have an expiry period? What else would explain his ten-inch pecker getting a budget cut to six inches?

'System, why is my penis shorter all of a sudden? Are the Engorgement pill effects wearing out?'

[Processing…]

[Engorgement pill effects are permanent. No information on the shortness of user's penis]

Ethan bit his lip anxiously, feeling his erection soften. The gods of Promiscua were again being unjust and unfair. The boy was thrown face-first into an exciting porn fetish scene, but tragedy immediately followed it. Did the gods not realize that nothing could be more emasculating for a man than having a random penis reduction?

"What are you waiting for?" Ivy asked impatiently. "Are you enjoying seeing me in this humiliating pose? Does that turn you on?"

Ethan wanted to answer, "Yes, I enjoy your humiliation," while he actually replied, "I'm consulting my notes on the Devil's curse to be safe. "

"Alright. Just hurry!"

Ethan took a deep breath and went to his second-best source of information. The book—GIRLS! GIRLS! GIRLS! A guide to self-discovery for humans, elves, and adventurous orcs, by the author Jack Mehoff.

Jack was a legendary warrior turned medieval playboy, and definitely blessed with fertile seed. He must have valuable insights on the subject.

Ethan retrieved the book from his inventory and plopped it on Ivy's butt. "Sure! Use me as a table for your studies!" his sister snapped.

"Shut up! I'm doing this to help you. You wouldn't be stuck in the tunnel if you didn't have such a fat ass."

The Cromwell heir could hear Ivy's muffled gasp in response to his insult. Instant silence followed. His sister shuffled her knees uncomfortably as if trying to make her behind look smaller.

Ethan ignored her futile attempts and scanned the book's index. He found a dozen entries related to penis shortening. Most of the causes were witch curses, alchemical failures, and natural accidents. The boy's search came to a halt when he came across an entry that mentioned the Chaste Devil's Curse.

'Male fertility is a bane in disguise," Jack Mehoff wrote. 'On one hand, you are a rare specimen, capable of becoming wealthy overnight. On the other hand, you are inflicted with unimaginable curses."

'The principal among them, of course, is the Chaste Devil's Curse, which may kill the fertile male within hours of being aroused. This is a well-known fact."

'However, a little-known affliction exists only observed in early adulthood. I call it the Neuter curse.'

'I have noticed, in a few unfortunate cases, that the boy's manhood may get reduced if desire fulfillment is delayed. How terrible!'

'Anyway, most fertile men get plenty of young, juicy honeypots and hence never experience such genital deformities. Only the most foolish and incompetent may fall prey to the Neuter curse."

Ethan let out a heavy sigh. Indeed, he deserved the tags of foolish and incompetent more than anybody else. By playing with his prey, he delayed his fulfillment and, in turn, triggered the most emasculating curse ever.

"Are you okay?" Ivy asked. "Your sigh reeked of disappointment. Did you find any useful information? Or are you having trouble getting your thing up? I heard some men experience such problems."

Ethan did not respond to his sister's concern because his dick bounced up into a formidable erection. Ivy's humiliating talk was doing the trick.

The boy shuffled forward on his knees and lightly placed his dick against his sister's right asscheek. She flinched as the hot foreskin touched her. "Is that thing what I think it is? Why is it so burning hot? Your body is weird!"

Ethan inhaled deeply, getting tremors of encouragement from Ivy's abuse. He grabbed his dick and slapped it hard on her exposed butt.

"Ow!" his sister exclaimed. "Are you playing games like a child? Just get on with it!"

The Cromwell heir grunted and pressed a hand on Ivy's back. It forced her abdomen to go down and propped her ass up. More of his sister's pancakes were available for free use.

The boy slipped his dick horizontally in her crack. He began moving his hips, enjoying the friction between his hand and the partition.

As his arousal climbed, Ethan felt an overwhelming urge to pull down Ivy's panties and fuck her pussy. But he didn't want to ruin the deal and successfully fought the impulse.

"I'll have to be a little more rough to reach orgasm," he said innocently.

"Go ahead…" his sister replied through shortness of breath. "Do what you must, as long as you don't pull down my panties. Keep your actions outside of me."

"Yes, ma'am…"

While his dick was firmly lodged in the crack, Ethan grabbed the girl's asscheeks and pushed them together, forming a tight cleavage. Now, he actually had something to fuck through.

Spotch! Splurch! Spotch! Splurch! Within a minute of dry humping, the boy discovered something incredible. A wet patch developed in Ivy's panties, precisely around the area of her pussy. The wetness seeped through, lubricating his penis.

Splotch! Splotch! "Ivy… Are you wet?" Ethan asked, between thrusts. "Are you enjoying this?"

"Let's not talk, okay?" his sister growled. However, she could not mask the arousal in her voice. The stuck girl's body was already trembling, and she let out quiet gasps at intervals. A thin film of sweat covered her back and drenched her shirt.

Did Ivy want him inside of her? Was it that time already?

Ethan did not even bother asking Ivy for permission this time. His reptilian brain took over, triggering his suppressed primal instincts. The boy took the tip of his penis and tried to force it into his sister's pussy through the panties.

"Ouch! What the hell are you doing?" Ivy screamed, resisting wildly.

"Didn't we agree to not talking?" Ethan retorted, grabbing onto her waist to prevent her wriggling.

"Not when you're trying to fuck me, you moron! We agreed to outside play only! Stop whatever you're doing to me right now! Control yourself!"

However, Ethan was too far gone already—to the point of no return. With a heavy thrust, the tip of his dick partially found a way inside along with the cloth. "Ah!" Ivy exclaimed, tightening her pelvic muscles.

Ethan's dick was caught and roughed up in her partition. The very shock of it, coupled with his sister's erotic moan, made him react too fast. It triggered a thrust into Ivy so wild he regretted it immediately. A patch of red appeared on her panties.

"Ahhh!" Ivy's scream echoed inside his closet. Her body convulsed as if having a fit. The girl closed her eyes, and her verbal outburst turned into an elongated groan of pleasure. Was Ivy cumming?

Ethan's penis sprung out of the ass sandwich and shot a load of cum over the girl's sweaty back. He didn't even get a chance to aim!

As the boy shuffled back, taking control of his penis, a second load splashed on her panties, dripping into her crack. A lot of the substance seeped inside, mixing with her wetness.

[Challenge completed: Get an assjob]

[Reward: ?????]

[Reward will be available soon]

'Wow, that was intense,' Ethan thought, his heart palpitating like a wild beast. He had enjoyed the two sexual encounters with Elaine and Hilda, but this was something else—an indescribable experience.

Ivy collapsed in her position, drained and gasping for breath. The severed ghost hands keeping her captive dissipated immediately. Even the bruise marks on her shoulders and wrists healed themselves.

Ivy's eyes opened as the weariness and anxiety washed away. The girl experienced a surge of energy and a plunge into peace.

Ethan quickly wiped his dick on his sister's panties and tucked it inside his boxers. Interestingly, he noticed a fresh rune manifest on Ivy's lower back where most of his cum had landed. It looked exactly like those on Elaine and Hilda. Mysterious tiny spirals. What did they mean?

"What just happened?" Ivy asked, quickly slipping out of the tunnel. "How did my hands get free? I didn't even consume your seed!"

"I think the rules are more complicated than we understand," Ethan replied. "Perhaps even the mixing of our juices qualifies as consumption."

Ivy nodded, still looking perplexed. "But then… I know for a fact that the effects of fertile sperm are singular. I feel a lot of versatile changes within me. Even my lost magical power is getting replenished as we speak. What the hell is this?"

Ethan shrugged with pride. "Well, my seed has magical properties beyond the feeble effects you've heard of, especially when it comes to humans. It probably cures the target of all ill effects at one go, and replaces them with beneficial ones."

"It is like an elixir," Ivy said with a hint of admiration, shuffling forward on her knees.

Ethan raised an eyebrow. "That's an interesting way to phrase it."

An awkward silence followed. The siblings knelt inside the closet, their faces inches from each other. Ivy was frustrated, bruised, and spent moments ago, but now she was healed and rejuvenated. It was an exhilarating experience for her.

The girl suddenly remembered she was in her panties, soggy ones. She tried to pull up her shorts when she suddenly noticed the red patch between her legs. Her eyes widened, and she looked up at Ethan in disbelief.

Ethan watched Ivy's mood change from joyful to disgusted. Tears welled up in her eyes.

Slap! She clocked one on her brother's face. "No, you didn't! Savage! How dare you! Godforsaken monster! I'll kill you with my bare hands!"