He tests the defective one on himself

Your father decides he doesn't want to test a weird new nanobot technology on his beloved daughter, especially if one of them is supposed to be defective. Instead, he'll test the darker colored patch on himself, to make sure they are safe, before trying one of the remaining two on you or your mother.

You look up at your father with worry in your eyes as he peels the backing off of the patch and applies it to his pelvis, just above the root, sticking it directly in front of your eyeline from your perspective of having his cock still jammed down your throat for all this time. The words 'FUCK TOY' on the patch fills your vision.

You are pretty used to holding your father's current size fairly comfortably, since your throat has been well trained through hours and hours of watching television on the couch with him while he idly jerks off with your head. You've barely even gagged on him since that three day weekend he binge watched every episode of a six season serial drama with your face buried in his lap. You weren't very interested in the show, but he tried to hold your head in a position where you could watch anyway. He considers it bonding time with his young daughter.

Now you're feeling a bit worried about what the effect of this patch is going to be, especially if he's not going to remove himself while it takes hold.

Kevin feels a light pinch of billions of nanobots flooding into his body from the patch. They work their way into his bloodstream then immediately get to work on his dick. He isn't quite sure what they are doing, but he can feel your throat getting tighter and tighter around him as his girth begins to expand.

You become even more concerned as the pain begins to grow along with the size of your father's giant cock. You can feel the new artificially enhanced length forcing its way further down, already beginning to reach the depths John's huge cock reached earlier, then passing it. You finally begin to struggle as your jaw is **** open well beyond its limit and you begin to wonder if he's going to end up penetrating your stomach with the giant head.

"Oh God, That feels great!" Kevin exclaims, enjoying the feeling of your already tight throat getting ever tighter as the nanobots finish expanding his tremendous size. He attempts to pull you back so he can begin fucking your throat, but finds he can't withdraw even an inch with your stretched out neck holding him inside. "Uh oh."

Both of you begin pushing against each other with all your might, trying to dislodge the gigantic member. Your eyes stream with tears and you lose your breathing as you struggle, but it doesn't budge at all.

"Huh. It's really stuck in there." Your father says as he gives up for a second to examine the situation fully. "Calm down and breathe, pumpkin... All we have to do is get me off and it'll go down, right?"

You make an attempt to nod in agreement and calm down as best you can, trying to get any amount of oxygen in through your nose. You get in just enough to stay conscious, but you feel like you're trying to breath through a coffee straw, as your father begins pulling your body back and forth the fraction of an inch he can, trying to get enough stimulation to orgasm.

"Oh man, that feels really nice," he says, moving you faster and faster, as you lap at the small portion of the underside of his cock that's laying on your tongue, trying to help so you can end this misery.

Unfortunately, he can't get very much stimulation on the huge glans poking into your stomach, prolonging your **** for more than twenty minutes, though to you it feels like hours of trying to get him off.

"Ugnn, finally..." Your father groans, firing a fresh dose of medicine directly into your belly, splattering his copious seed against the walls of your stomach as he fills you up with a huge load proportionate to the new size of his cock. You feel wad after wad moving through his urethra, traveling over your tongue, down your throat, and exploding out the tip and into you.

By the time he finally starts to slow down, you feel as though you've eaten a huge meal of just your father's cum, with gallons of it sloshing around inside you. He moans one last time, trying to pull out of you.

Then tries again, pulling you harder, but his nanobot enhanced erection refuses to go down at all.

He looks at the instructions on the back of the patch again.

"24 hours, huh?"