"Ah chico, I think you already know the answer. It's making you into exactly the lover that I want. Mamma Mia needs a nice big juicy cock to keep her satisfied."
Mia reached down and started idly playing with her stepson's manhood, rolling his swollen balls between her fingers then tracing her fingernails up the length of his hardening shaft. Even after a long day of fucking his insatiable shemale stepmother, Tommy's cock quickly stood to attention, and he could feel yet another huge load of cum churning within. Not willing to let his confusion stand in the way of such pleasure, Tommy leaned in and started sucking on Mia's proffered breast with gusto.
"But how?" Tommy asked between sucks as Mia began pumping her hand up and down his cock with greater intensity.
"I told you chico," Mia answered as she used her free hand to press Tommy's head back down onto her saliva-coated tit, "Mommy's cum is loaded with hormones that will make you grow big and strong."
With his face pinned to Mia's chest, Tommy glanced down at his fully-erect member and mentally compared it to Mia's own. When she'd first seduced him in the shower a month ago, her impressive 8-inch monster had dwarfed his admittedly average endowment, but now they looked to be almost the same size! He knew he'd guzzled more cum from Mia over the past month than he would've thought anyone could produce in a year, but could it really have such a pronounced effect? And where those changes also the reason he came like a fire hose every time, even with the constant releases?
Tommy's musings were curtailed by Mia's horniness. Eager to get some action of her own, she rolled him over onto his back and hopped on top, straddling him in the 69 position. For all their experimentation over the past month, somehow they'd never tried this position before, and Tommy was a little surprised at first when Mia dropped her hips and pushed her cock into his mouth. The angle was different than what he was used to, and pinned between Mia and the mattress he had next to no control over the pace or depth of penetration, but his trained reflexes swiftly kicked in as he started sucking and schlurping appreciatively. Mia continued to pump Tommy's cock with one hand, cradling his balls in the other.
"Is Mommy's big boy going to keep taking his medicine?"
Tommy grunted in affirmation while reaching up to grab two handfuls of Mia's ass, pulling her thrusts down deeper as he worked her cock down his throat. Giggling at his eagerness, Mia rewarded Tommy with one long slow lick from his balls all the way up his shaft, finishing with a playful twirl of her tongue around the tip.
"This is Mommy's toy, I made it what it is, so I decide what happens to it, understood?"
Again, Tommy could only groan his assent, as Mia's cock was plunged deep into his throat with unabating passion. She'd bottomed out now, and her balls were resting on her prone stepson's face as she continued to fuck his unresisting mouth. She rewarded him once more, this time expertly sliding his entire eight inches straight down her throat until she was nuzzling his balls. They'd grown from the size of grapes to a pair of ping pong balls, struggling to keep up with the demands of their incestuous sexcapades. As Mia slid her lips back up Tommy's cock, she clutched his swollen balls in a tight grip, lightly digging her fingernails in with slowly building pressure.
"And if Mommy wants to play rough with her toys, she will." Mia punctuated her statement by taking the head of Tommy's cock into her mouth once more and nipping the top of his shaft in a playful bite.
The pain was exquisite. Tommy had never experimented with masochism before, but the sharp sensations amplified everything else until the entwined pain and pleasure were unbearably intense. He felt his balls begin to clench, struggling to pull into his body as his body raced to a sudden orgasm, but they were unable to escape Mia's cruel grip. As Tommy teetered on the edge of climax, Mia slid her mouth up and down his shaft, scraping it's length with her teeth. Still Tommy was powerless to obtain his desperately needed release, as the vice-grip on his sack held him back.
Mia held Tommy in that precarious state, teasing him with pain and pleasure but holding him from release, until she felt her own orgasm approaching. Only then did she relinquish her hold, allowing his tortured balls to blast out their long-building load. His convulsions as he pumped his cum into her mouth pushed Mia over the edge as well, and she matched him blast for blast as she shot her cum straight down his throat.
While Tommy was recovering from the shock of his earth-shattering orgasm, miss deftly dismounted him and turned, leaning in for a kiss. Tommy unthinkingly obliged her at first, but recoiled when the taste of his own cum met his lips. Her cheeks puffed out with the cum she'd just milked, Mia said nothing, but roughly seized Tommy's cock and balls in one hand while taking a fistful of his hair in the other. When Tommy predictably gasped, Mia swiftly resumed the kiss and spat the whole load into his mouth. Only after her reluctant stepson had swallowed every last drop of his cum did Mia release her grip and end the kiss.
"What the fuck was that?" Tommy exclaimed as he stood up and looked about for a cup of water, or anything to get the taste out of his mouth.
"You mean that little taste of pain? You seemed to enjoy it," Mia bantered.
"No, that was fine, but making me swallow my own cum?"
"It came from my toy, that makes it mines
to dispose of, and it wanted to see you eat it."
"But it's fucking disgusting!"
"It's no different than Mommy's cum, are you saying that Mommy's cum is disgusting?" Mia shot back with a hard edge in her voice, as if daring him to answer. Tommy's rage evaporated as he meekly shook his head.
"Your cum is filled with the same hormones as Mommy's now," Mia continued in a more reconciliatory tone. "The more you drink, the faster this is going to grow."
As Mia started playing with Tommy's cock, his hesitation was overcome with curiosity.
"So how big will it get?" he asked as his cock began to harden again in response.
"I'm not sure chico," Mia answered, sliding off the bed and kneeling in front of him. "The doctors said something about 'natural equilibrium' and 'meeting the limits of the body', but I think that was just their way of saying they don't know."
Tommy was fully erect now, and surprised to find that the idea of eating his own cum was no longer abhorrent to him. In fact, it kinda turned him on. And the sight of his hot stepmother kneeling in front of him, sliding both her hands up and down his newly supersized manhood certainly didn't hurt.
"Well maybe we'd better find out for ourselves," Tommy finally offered, "wanna get me another load?"
Mia smiled and set right to work, expertly extracting another load of cum from her willing stepson, then standing before him with it filling her mouth. Tommy hesitated for just a moment, running his hands up and down Mia's body before pulling her in close and locking his lips with hers. As their tongues danced in unison, Mia cleverly worked each drop of cum into Tommy's mouth one bit at a time. He allowed each one to slide down his tongue before swallowing. She was right, it really did taste just like hers.
The next day Tommy woke up with an epic case of morning wood. He'd dreamt all night about wild sex orgies in which he was impossibly endowed with the sort of monster cock that could only exist in the realms of fantasy, but as he looked down at the large tent he was making in the sheets, Tommy had to wonder just how close to that fantasy reality could come. For now, though, Tommy had more pressing concerns. He rolled over to Mia and took a moment to soak in her beauty. Her hair was spread wildly across her pillow like a raven-black mane. Her face was the image of feminine perfection, with her delicate features and soft full lips.
The sheet had fallen to the middle of her torso, exposing the twin mounds of her beasts. They were twin works of art, a pinnacle of man-made perfection which utterly surpassed any natural creation. Tommy knew from his time raiding Mia's panty drawer that they were G-cups, but their beauty was in far more than their size. They were perfectly round, with no scars or blemishes, and even without a bra they never seemed to droop or sag. Even now as Mia lay on her back, they stood proudly, meeting in the middle of her chest in spite of gravity's pull.
Tommy lowered his head and took one of Mia's nipples into his mouth, swirling his tongue around her large areola while teasing nipple into hardening. Mia awoke with a smile on her face, enjoying her stepson's devoted ministrations.
"Mmmm, chico, Mommy is so glad that she taught you that little tongue trick."