Fuck it out!

"Kako, why don't you stop that, I can tell its turning you on, and I don't want to explode because you pumped another gallon of cum into my bowels." She gives you a sheepish look and lets her cock go.
"How are we going to do this, without making me cum? I already feel all horny trying to get it out this way," she says thoughtfully. You guide her to the floor on her back, and tuck her cock between your legs.
"I am going to get mine now," you command, and lift up her sac and rest it between you as you get a grip on her ass cheeks and spread them.
"Naughty boy, I see...You won't be able to respond to the pain when you cum, and that's when I should pull it out," Kako says, praising your plan. "Of course, this is no excuse not to get you looser," she adds, holding her sac up for you so you can enter her ass. You plunge it in quickly and release all that pent up sexual tension. Finally, you can fuck her! You push in as deep as you can, enjoying the feeling of her extra large bottom pressed against your crotch. You don't try to draw it out this time, in case something else happens. You fuck with the goal of cumming in mind. It only takes a minute or so, and you drive yourself deep and hold it there, "Kako pull it out when you feel it," you command as you are about to squirt. You let loose, and dowse her ass with your cum. You feel Kako give a quick tug on her cock, and it pops out of your ass. You finish cumming quickly, relieved to have gotten her cock out. You then feel her hand at your ass, and she pushes her fist in. She points to your legs, "You are covering everything with my cum, messy!" she chides. "Come soak me in cum instead!" She yanks you off balance, pulls you forward and sits you on her breasts. She withdraws her fist, and pure cum gushes out, washing over her.
You turn your head to watch, and feel the pressure leave your bowels. You couldn't close your ass if you wanted to. Kako looks like one of those Superbowl coaches who got drenched, but this isn't Gatorade, this is her own semen! You figure it really must be a gallon per load, as it trickles off. You turn over, and rub her all over, making sure every inch of her has a nice thick coating of her own cum. She of course does the same for you. You linger on her cock and balls, rubbing the cum in like lotion. During your ministrations, she grabs the end of her cock, and drags it up and puts the head at her mouth, and starts cumming again. She tries to drink down that gallon of cum, and mostly succeeds. You can see her stomach grow as she fills herself up. She finishes and pats her swollen tummy. "I thought I had enough on my outside, so I put some inside," she says with a grin. You rub her tummy and give her nipples a tweak. Then you pull her up, and turn her over, and enter her ass again. This time its for keeps. You relish her large ass cheeks cushioning you as you slowly pound her, each time her ass jiggles obscenely. You enjoy a nice leisurely fuck, and then unload in her ass again. Both totally slippery and covered with cum, you both get to your feet and survey the cummy mess on everything. Kako goes around behind you and spreads your cheeks.
"Wow, you are gaping! I bet I could shove my fist up there without you feeling it hardly at all!" She doesn't wait for a reponse and does it. You feel it go up, but it feels as natural as using the bathroom. "Now then," you say, "what about you?"