She takes another hit of your cum

Aved at your sisters sheer size you can't help but want to see her grow even bigger, stronger, and bigger, also your sisters mouth is the best thing your dick has ever experienced. "Uh, maybe, maybe you could go bigger?" You tentatively ask your dominating sister. Seeing your longing and hopeful gaze a fire is lit in your sisters eyes and she picks up your bloated form with ease before bringing your litle boy cock to her mouth where she starts sucking. Your mind goes numb as absolute bliss envelops your mind, and you start cumming. Orgasm, after orgasm, Sarah just keeps emptying you of any and all cum you might have left, and she starts to grow. first it's just a twitch of her pecks, or a flex of her biceps, but soon her muscles are expanding faster than should be reasonably possible, and her height is approaching 8 feet.

Finally your stores run out, and you're tiny dick twitches madly with dry orgasm after dry orgasm. a full minute later your sister lets you go, but instead of the matress you were expecting you land on her gigantic organ. It's a full 5 feet in length now, and half a foot wider than before. You whimper at the thought of this wrecking your ass, but then a powerful hand reaches down to your head and starts stroking your hair. "Don't worry Dougie, I won't make you take that up your ass. Yet. No, I have plans for you, and I need you alive for most of them." You shiver at the sheer dominance that seems to emenate from your, now much more mature sounding, litle sister, and at the word 'Yet'.

Her muscled arms gently envelop you, before lifting you of her she-cock. "Come on down Doug. I need to gives this thing a test, and moms giant ass seems like the way to go, before I find a way to make you more 'accomodating'." She smiles evilly at you, before moving over to your **** mother and lifting her onto the tip of her mega-dick. "Oh yeah!" Sarah screams as she plunges a portion of her organ into her own mother, eliciting screams from the shemale as she wakes up. "Take it!" She pumps the poor woman's ass mercilessly for a full hour, as you watch, before cumming so much that it sprays out along her entire length.

With a sitisfied grin, your sister motions you over. "Come here Doug, and start licking. We need to fill you up again, and until you're ready for my titan you'll need to get your meals from me by cleaning my partners and me." She watches as you lick her, your mom, and the bedsheets clean, with viggour, since more cum in you, means more growth for your goddess of a sister. "Now, what to do with you?" She thinks out loud, tapping her chin.
(by ban on writing thread)