You make it fit!

You remember you don't need to be on all fours and let your breasts hold you up in front. Kako seems to be having trouble getting you both coupled. The largest obstacle is the mushroom head, which is the size of a basketball. You know the head will need to be squashed and turned to provide it entry. So you reach around back and work on squashing the head near the penetration point to allow it to squeeze in. You manage to smush it down to half its size and then it slides right in. Once it passes inside of you, you are no longer keeping it compact with your hands. You writhe as the head quickly expands in your hole, causing an immediate orgasm as the organ hits all of the right spots at once. You moan louder and louder.

"Fuck, Kako. That monster is huge!" You feel a combination of pain and pleasure as the invader pushes deeper over the flare of the head, causing you to go wider the whole time. Then your seal slips over the edge to grip the shaft, which ends the pain. "This is the most incredible feeling. I am ready for you to shape me as you see fit. You can do anything to me as long as it comes at the end of that expandable penis!"

"I thought you might say that. Here it comes!" Kako shudders, and the head expands inside of you in preparation of what is to come. You feel your gut expand as the head keeps strangely growing. You figure it has something to do with her brew coming. You push yourself up from doggystyle and part your breasts to look upon the cockhead stretching your front visibly. It reaches the size of a beachball and keeps going. You shudder in orgasm again, your tits leaking milk. You lean back, and see Kako's cockhead sticking out inside of you over your generous rack.

"Not much longer. The entire load needs to mix in me and be expelled as quickly as possible for maximum effect," Kako explains. You don't mind really. The whole experience is exhilarating. And then you feel a heaviness inside of you as the head expells its dense juicy load. The effects soon kick in.

Your previously generous rack kicks into high gear milk production, swelling your bust to double its previous size, not doubling the size of Kako's breasts like she said. They grow so fast your nipples begin to leak and then squirt a thin stream of milk. Your nipples lengthen to what you figure is a full foot and grow as thick as your dick. Your ass softens from your muscular form to a soft, round smooth and quite large bubble butt to put J-Lo's old one to shame. Your hips fill out and your thighs enlarge to give you the perfect thick female body. Kako pulls out of you while this is going on. She rolls you over onto your back as you shake from the transformation. She mounts your cum-leaking cock and places her cock into your cleavage. Then she hauls your breasts over her cock and tit-fucks you. It seems to barely fit. You feel your new chest parting for her cock. She leans forward.

"They had to be big enough to tittyfuck, silly!"