Give it another try!

You smirk at her promise. You ask her to get up on her hands and kness. She eagerly complies. She looks back at you, inviting you inside her asshole. She looks wonderful. Every part of her reflects the light, from her hanging breasts, to her pale perky ass. You jump into her, literally. Her cock is hanging around and trails behind her. You lovingly put it between your knees as you enter her ass, wanting her to feel pleasure too. She fucks you back as you fuck her. The feeling of her slippery ass cheeks beneath your hands makes you want to blow instantly, but you hold off to enjoy it longer. You decide to take your mind off of it by rubbing her cock between your knees, and stick the head upward between your feet so you can reach back with the other hand and rub the head. It quickly toughens, but doesn't grow stiff. You realize with a cock this size there's never enough fluid in her to make it completely rigid like a normal cock, it will always remain flexible when erect, but hard enough to penetrate, you figure. You reach around to fondle her breasts, just while she had the same idea. She pulls herself upright with your cock still in her ass, and you lose your grip...AGAIN! Your balance is thrown off, with your legs and feet at odd angles working your girl's cock, and her tits slip out of your hands and you fall backward and throw your hands up behind your head to cushion your fall. You successfully manage to only smash your knuckles against the floor, but also feel a pain at your asshole. You look at Kako who is laughing wildly, but is also obviously turned on. You look down and see what the pain is. Her monster cock head is lodged several inches into your butthole. Not the entire head mind you, but enough so you feel stretched beyond capacity. You wince as her cock grows from her arousal, the increased size stretching you further. You reach down to yank it from your tender virgin asshole.
Kako stops you, "Now, now, don't do that," she scolds half-seriously, half-playfully. "How will we ever get your asshole ready for me without practice? You already experienced the initial pain, just ride it out until you get used to it...for me?" You nod your head, and brace yourself again, and try to relax as much as possible with the pain in your asshole. After what seems like hours, you realize that while you are still sore from the initial penetration, you have relaxed enough so that the monster cockhead doesn't bother you anymore. Kako sees this, and withdraws her head from your ass, gives it a few quick strokes, and releases another load of cum all over you, while she says, "I was holding it forever...I didn't want to cause you any more discomfort by unloading up your ass."
You prop up on your elbows as a few load splatter against your body. "Well can you at least give YOURSELF the majority for once?!?" She quickly points her gyser at her chest, and rubs the spurting head all over her body, giving herself a dripping coating rivaling your own. She rubs it around and sprays all over her ass too, "Keeping myself lubed up for you," she comments. You watch her orgasm with interest for minutes, until she comes down from it.
"How are you feeling?" she asks with concern in her voice. I shouldn't have **** myself to stay inside you, but I just love the feeling of my cockhead wrapped between your ass cheeks."
You tell her, "It doesn't hurt anymore, I was just surprised as I never thought about having any cock up my ass before. Guys just disgust me sexually, but I can't say I don't like to use my ass once in a while when I'm alone. I rather enjoyed the sensation of your spongy cock; it's better than the hard plastic I usually stick up there." You continue to reassure her that you enjoyed it until the worry lines disappear off of her face. "So don't worry! Why don't you pick our next activity?"