Infiltration

You decide to first check the house. A bit of information will allow you to get close enough to the females that discovering the ruse will matter little. It's a nice place, though primitive by your standards, and seems a bit upscale for what is typical of this planet. Pictures adorn parts of the wall, featuring the three humans you have so far seen in the house as well as others, though their lack of repetition suggests they do not reside here. Garments typical of their mating ceremonies feature one picture of the male and female, their ages significantly less. Pictures of the younger female at varying stages of growth confirm the situation as the typical mating pair and their offspring.

Based on gathered knowledge of this planet's culture, the male is likely to be gone for several hours at least. More than enough time for you. A quick rifle through some personal effects gains you a bit of knowledge about your targets, and you decide to make your move.

The mother faces away from the house, sunning herself as the daughter swims about playfully. Though the humans have long since lost the ability to sense pheromones consciously, you are keenly aware of both ripe females, and have to remind yourself that it's still possible to be exposed at this point.

"Dad?" The daughter sees you as she rests against the side, gazing quizzically at you. The mother turns to see you, and sets down her book as she stands up. "Something the matter, dear?"

You shake your head and smile. "No big deal. I just forgot something. Figured I could get one more kiss before I left again."

It was a bit of a gamble, but the photos had suggested an affectionate family so you went with it. When the daughter pulled herself out and grabbed a towel and the mother grinned and walked over, you knew it had paid off.

"Of course, hon. A week is a long time to be away." She wrapped her arms around you as inwardly you laughed. The situation was better than you had imagined! You lean in for a kiss as the daughter wraps her hands around you both. "We'll miss you, Dad! But don't worry, I'll take care of M-"

Her words are cut off as you spring your trap. The many tentacles you'd been holding back burst out, wrapping around both of them before they could so much as blink. Any calls for help are silenced as you gag them, thrusting deep into their mouths, and you drop your guise. The horror and disbelief at what they are seeing is palpable, even as you strip them of their meager garments.

Tentacles wind their way around their ample tits and begin caressing their lower lips, drawing struggles and muffled protests. The slime oozing from the tentacles slicks up their bodies, and their effects begin to work on their resistance almost immediately. Neither can help but swallow as more and more of it runs down their throats, and you grin as their pussies grow ever wetter.

Unable to hold back anymore, you roughly shove two tentacles into the mother's pussy, and another into her ass. You wait only seconds before grabbing her hips and pushing your engorged main cock in alongside them, stretching her obscenely. She arches her back in pain and very unwelcome pleasure, trying to get away despite the futility. She is extremely tight, even without three cocks in her, and you hit her cervix only about 2/3rds of the way in.

Not wanting to leave her out, the tentacles holding the daughter are working as well. The ones at her tits begin rubbing her nipples, teasing her mercilessly through the fear. The tiny tendrils inside them extend outwards, pushing into her nipples one at a time and drawing screams of terror from her that die in her throat. Another pair wind around her neck, their tips twisting around till they press into her nostrils. Her eyes bulge out as she feels more of the tendrils worming into her nose, twisting around in her sinuses as you **** her face. The slime oozes everywhere, eventually beginning to come out of her tear ducts even as she fights the chemically induced arousal.

Thrusting in and out of the mother viciously, the tendrils in the tentacles inside her are probing the tight ring leading to her womb, slowly opening it and relaxing the muscles. The bumps and ridges of your cock work with the aphrodisiacs to begin an orgasm in her, and just as both tentacles finally **** their way into her uterus it crashes over her. Her eyes roll back as she shakes uncontrollably, the daughter shaking her head back and forth weakly in an effort to stave off a similar feeling.

The tentacles stretch the mother's cervix wide, allowing full penetration as you slam home. The moment your crotches meet, she wraps her legs around your waist and holds on tight as you thrust ever more forcefully into her. Even as she regains her senses, she seems unable to order her body to reject you, moaning under the pleasure despite herself.

All the while, the daughter's nipples are opened up and the head of the assaulting tentacles are able to push inwards, extending their tendrils deep into her never used milk ducts and stimulating production. The arousal grows too great amid her drowning in your sexual fluids, and she too rocks in orgasm, her hips beginning to thrust in need at your lack of attention to her pussy.

The tentacles inside the mother's uterus move on their own mission, pressing up against her fallopian tubes and sending many tendrils into the tiny passage towards her ripe ovaries. Her womb already contained an egg of her own before you began, and you would soon lay many more inside her, but your semen could easily fertilize humanoid eggs as well. The tendrils now stimulating her ovaries send them into overdrive, encouraging the production of many, many eggs that would begin to ripen within a few hours.

By now you're ready to cum. "Ok, 'darling', time for your first seeding. They're pretty big, so get ready. I'll be sure to fill you with plenty of semen to fertilize both mine and yours." A muffled "No!" escapes her gag, but she still is unable to unlock her legs from around your waist. You couldn't pull out even if you wanted to (which you don't). The first egg forces its way up your cock and into her womb with a PLOP, soon followed by the rest in quick succession. Her belly grows visibly with each one, and by the eighth she's orgasming uncontrollably for you.

As the last one finds its new home, the tentacles along side your cock erupt in a thick syrup, immediately fertilizing the large eggs as well as the one of her own already floating around. Many more would join it soon enough, and there would be plenty of cum to go around. As you pull out, your cock secretes a resin-like substance to seal off the entrance and keep anything from escaping, ensuring her now 5 months pregnant looking stomach would stay that way for a while.