Endurance. Obedience. And Secrecy. His father mustn't find out.

James was sitting crosslegged on a pillow in the middle of his room, his heavy nuts weighing down heavily on his legs - in part because his equally weighty tits were resting on them, James' ramrod-straight, throbbing cock sandwiched between them, reaching up to his chin. James' hands, however, were neither jerking his monstrous shaft nor fondling his enormous tits. They were both bound behind his back.

Not with rope or shackles or anything so crude. No, just a single piece of string wrapped around James' wrists, thin enough that it could be snapped with ease. Because this was neither punishment nor a kinky power play by his mother; it was a test. The first of many, Anne had told her son, but should he fail this one, not only would she be most disappointed, but it would be the end for James. No further training would be possible if he didn't even manage to pass his mother's first test.

Obviously, due to James' uncontrollable libido and his impossibly sensitive tits, his over-eager cock and balls it was of course only a matter of time until James made another mess - and Anne knew this. But this was not a test on how long it would take.

It was a test of James' willpower. It would be so easy to snap the string. Free his hands to fondle his boobs, aching to be touched, jerk his cock, pulsing angrily and slowly drooling pre. But his mother would know. She would see James' wrists were no longer bound, see the snapped string, and then Anne would make that disappointed tutting sound. Not to mention follow through on her promise never to touch him again - and while James knew that he'd irrevocably altered his mother's body, made it so only his cock would ever satisfy her again, he also knew that Anne would absolutely keep that promise.

So James sat and did his best to endure. Until his mother decided he had passed.

James was trembling and twitching, every breath a moaning sigh as rivulets of pre cascaded down his shaft, slickening his cleavage marvelously. The slightest movement was stimulating beyond compare, reaching almost the level of his mother's silken walls. The need to cum was almost primal, James' restraint put to the test harder than he'd ever expected.After all, why shouldn't he just snap the flimsy little string and jerk himself off? The way he felt, it would be a matter of seconds, and then he could figure out a way to re-tie the string so his mother wouldn't--

"Ah, my little pervert." James jerked upright, boobs jiggling and setting off another spurt of pre. His mother entered his room in her yoga pants and a tight, pink off-the-shoulder top that showed a hint of trim midriff, hair held back by a sweatband. She looked as if she'd stepped right out of a 90s fitness instruction video - and her clothes left nothing to the imagination. "Have you made a mess, you naughty boy?"

James simply gaped. He wanted to jump up. He wanted to run over to his mother, bury his face in her firm breasts and his cock in her snatch, hips bucking as he imagined railing the cunt that had birthed him and that he'd resized to fit his massive shaft. The only thing that kept him firmly in place was the haughty stare Anne gave him as she rounded him, eyes running down his pre-coated length and the slick swell of his bosom. As she passed behind him, James heard his mother make a small sound - and his heart trilled. Did it not sound like satisfaction?!

"Well done, James." The smile Anne gave her son was almost... warm. "The string is in place. And you have even managed to keep from cumming... You are making mommy proud. So very proud."

James' heart skipped a step. In all his life, Anne had said three times that she was proud of him. Once when he had won first prize at the middle school science fair, once when he had passed all courses in his junior year with As and once when he'd been accepted for the marine biology course at the local college. And every time, she'd followed it up with a qualifying statement. That he could have improved his presentation, or that he could have taken more AP classes, or that he could have been accepted into a more prestigious college if only he'd applied himself more. This was the first time, the very first time that Anne was simply proud of James. No strings attached. Well, except for the one around his wrists.

"Ohoho, are you feeling motivated, little pervert?" Anne's chuckle was filled with genuine mirth as she saw James straighten, fists and jaws clenching as he felt his determination rise. "Then let mommy give you a little reward... before we continue this test."

Once again, James felt his heart skip a beat. Not because his ordeal was not yet over. He knew he could do it. For his mother. No, it was because Anne was slowly bending down towards him, her lips parting slightly as she neared the dripping tip of his cock, then opening wide with her tongue extending so she could wrap them around the tip of her son's fat glans and lap up the copious amounts of pre spilling forth even harder now. James groaned deeply, jaw now slack as his mother slobbered over his swollen purple helmet, slurping up his salty pre-cum and swallowing it eagerly.

"Ah--guh! Muh-mommyy..." James bucked his hips, body trembling under the pleasurable ****. He had to cum, he had to cum, he had to--

"Mmmh, you naughty boy..." Seconds from the point of no return, James' cock already straining and his giant balls twitching, Anne suddenly pulled back, wiping at the corners of her mouth with her pinky to clean up any stray drops. "I could get addicted to the taste. Does that excite you, little pervert? Your own mother lusting for your ridiculously oversized monstrosity of a cock so much she slurps up every... single... drop?"

The mental image alone was almost enough to send James over the edge. The breath caught in his throat, and a particularly big glob of pre was jettisoned from his distended urethra, dropping back down to ooze down his shaft where it was scooped up by his mother. The touch of her delicate fingers made electric shocks race through James, sparks of light seeming to dance before his eyes.

"I see, little pervert, I see. Then make sure to make lots for me..." Anne stood back up and strode out of the room, giving her son a spectacular view of her backside before turning back towards him as she was about to close the door. "And show mommy how much you want her. If you manage to keep from touching yourself until the evening... well, your father will be home late today. Very late..."

The door closed, and James stared at the wood, his mouth suddenly feeling dry - and his cock ready to burst.