Grandpa Max had taken Ben and Gwen to the beach to go swimming. He had almost immediately lost track of them, but he knew that they would be safe, as if anything bad happened, Ben would be able to handle it, or at the very least, he would make the situation obvious enough for him to find them and help out with whatever was happening. He wasn't aware that Ben was the problem, and Gwen was the target.
Gwen had almost thought that Ben would leave her alone, seeing as they were in a highly public place with many other people about, and in truth he almost had. But once Ben saw Gwen in her swimsuit and nothing else, he decided immediately that Gwen would be leaving the beach with little to no feeling in her legs, even if he got making sure of it.
He started out fairly basic, just swimming behind her, reaching under the water, and pulling her swimsuit aside so he could fuck her underwater with no one noticing a thing so long as Gwen held a straight face, which he knew full well that she could. He plunged his cock into her, groaning in pleasure at how good it felt when he thrust his hips against her, feeling the cold water against his cock followed by the comfortable warmth of Gwen's pussy.
Gwen grit her teeth, and kept her poke-face so as not to draw any attention to herself or Ben, making sure that Ben was conspicuous enough to not be noticed by any of the other beach goers. Ben grunted, hammering into her harder and harder for several moments, then pulling out when he came before leaving her. Gwen sighed, not even thinking about why Ben hadn't finished inside of her like he usually did, figuring he had just let her off easy for one. Unfortunately not.
She froze when she felt Ben, having transformed into Ripjaws, having grabbed her hips under water. He ripped the bottom of her swim suit off and plunged his long, fat tongue into her pussy. Gwen whimpers at the size of the alien fish creature's tongue probing her pussy, her legs locking around Ben's head as he forced all five inches of his tongue into her cunt and swirling it hard.
Ben loved how she tasted, and had not wanted that tasted muddied by his cum when he ate her out. Gwen bit her tongue so hard it nearly started to bleed when Ben made her cum against her will, knowing that Ben was enjoying the taste of her juices made the climax feel hollow and bitter sweet, as bad as if he had simply cum inside of her if not worse.
But Ben wasn't even done. He pulled her underwater hard, sinking his cock into her pussy aggressively, going into a fucking frenzy under water where no one could see or hear Gwen. She tried not to panic, knowing that Ben wouldn't actually let her drowned, but she was all to aware of the fact that Ben was swimming deeper and deeper underwater as he fucked her, pinning her against the ocean floor and fucking her hard against it.
Gwen held onto Ben hard, bucking her hips hard against him, knowing that she would let her up to get air once he came. Ben grunted, her movements making him cum hard into her, filling her pussy with watery cum. To her dread, Ben didn't let her go, pulling her right back down when she tried to swim off and thrusting right back into her, fucking her as she slowly ran out of air.
Gwen slowly lost consciousness, unaware that Ben was actually getting off on how much control he had in this situation, and continued to fuck her blacked out body, cumming twice more into her before he carried her up for air before any real damage was done to her. He wouldn't actually let her drowned, but for a few moments, Gwen had thought that he would and known that he could, and the look of fear she had given to him had made him cum harder than he ever usually did.
Of all the aliens she had been forced to fuck thus far, Stinkfly had to be one of the worst to deal with. He may attempt to drowned her with Ripjaws and stretch her holes far too much with Fourarms, but Stingfly's natural stench was far too unbearable, and Gwen was forced to smell it for every second that Ben fucked her as Stinkfly, especially when he fucked her throat with the thin, foul-smelling member.
After filling her throat with rancid smelling cum, the taste and smell of which would never truly leave Gwen, Ben participated in what he assumed he had made up, but was actually a tradition mating ritual among Stinkfly's race. He held onto Gwen with his legs as he flew up high into the air, sinking his cock into her as he flew and fucking her harder the faster he flew, the combination of the adrenaline rush and the pleasure of mating her bringing Ben a feeling of pour euphoria.
It nearly gave Gwen a heart attack every time he did it, and nearly made her vomit from a fix of motion sickness and being surrounded by the potent stanch of Stinkfly's body as he flew and fucked her, cumming repeatedly into her, making her stomach extent larger and larger with each thick, gooey load of cum dumped into her small body.
When Ben landed, he was hornier than when he had taken off, and he held her down beneath his larger body as he railed her with all of his might, slamming into her hard and fucking her abused pussy harder and harder until he came at least fifteen times, as Stinkfly's species was known to breed for hours before even getting tired, a fact that haunted Gwen.