"Ya know," said Kim. "we should get Mom in here. I wanna see if I'm bigger than her!"
"I'll go get her!" volunteered Alice. "We played together earlier!" She hurried out of the room, leaving you to be squished between your girlfriend's and older sister's scrotums.
"Having fun down there, sweety?" Becky asked, grinning at you.
"Oh I am just loving this," you called back with a heavy layer of sarcasm.
Soon enough, Alice returned with your mother, Hannah. Obviously, she had been informed her of the situation, as she was already naked. Her little 4" cock stuck out proudly from between her legs, however, it was quite overshadowed by the gargantuan orbs hanging down below it. They were extremely close in size to Kim's.
"So, where is my big girl?" Hannah asked, unable to see Kim from behind Becky. "By the way, good to see you, Becky. I assume my girls showed you a good time?"
Becky stepped away from Kim to face Hannah, taking you with her in her hand. "Oh, yeah," she said with a smile.
"That's good! Now, lets take a loo-- oh my god!" Hannah gasped when she finally saw Kim's engorged testicles. "Kim, sweety, you've gotten massive! How did these get this big?!" She rushed over and kneeled before her well-endowed daughter, weighing her cum tanks in her hands. "They're so heavy too!"
"She had a little help," Alice giggled, jostling her own sack a little. "It's not just her cum in there."
"Really? That's... Oh my god, that sounds hot just to think about! My little girl cumming in my big girl's balls. That must have felt incredible!"
"It really did," Kim said with a smile.
Hannah couldn't get enough of Kim's balls. She was completely caught up in their musky aroma, burying her face in the soft sack and massaging them all over. "Oh, Kim, these are beautiful!" She stood up, pressing her own nuts to Kim's. Sure enough, Kim's were bigger. "And they're bigger than mine!"
"You were right," Kim said, looking at Alice.
"These could be bigger, though," Hannah continued, her voice aquiring a subtly lustful tone. "A lot bigger. I'd be willing to... make a donation, if you want." She pressed her crotch against her daughter a little harder. Kim's cock couldn't have been harder. With Hannah's jizz in the mix, her nuts could potentially become twice their current size.
"Orrr..." Alice began. "We could let Mom join in on Pokémon!"
"I think Pokémon is a little played out by now, sis," said Kim. "I'm surprised, Will actually did pretty well, but we should think of a new game."
Hannah moved her face closer to her oldest daughter, pouting her luscious lips, her eyes full of lust. "Come on, sweety, don't you want Mommy to load your balls with her hot cum? Don't you wanna see them get huge?"
What does everyone decide on?