Kuu finally breaks the kiss. It may have been the longest kiss you have ever had, but it was still too short. Stroking your hair, she "asks" "So time to learn about unbirthing, right?" You of course nod eagerly.
"The best way to learn is by doing. You are a ways away from being able to do me, but you can manage to learn nearly as well by getting into me. So move down and get your head between my legs."

Soon you are staring up Kuu's body, from her center of joy to her magnificent mounds. She props herself up a little so she can see you. "Now you make use of that lovely tongue of your's to stimulate me." Now that is a bit of a stopper. Despite the bodies going down your throat, and your fun while Ben was playing with you, this is the first time you have been in a no-excuse lesbian situation. Granted, those were pretty feeble excuses, but...
Kuu seems to have had experience with reluctant newbies. "Oh, don't play the virgin. You know you are going to enjoy it." A hand reaches out to grab your head and suddenly your lips are entangled with her lower lips.
As she said, you are enjoying it. Kuu really does taste great and your tongue is quickly licking and probing everywhere within reach. You are not the only one enjoying it. Kuu is wiggling around as you continue to stimulate her, eventually resulting in her falling back with a sigh as she climaxes.

"That was wonderful, and now I am well lubricated for you to push yourself into me. So start shoving your head in there, and remember, I'll taste better the deeper you go."

That seems a bit unlikely to you, but you were enjoying her taste already, so you give it a try. Instead of pausing a bit away, you shove your nose and tongue into her damp heat and taste. She seems to be telling the truth, and so you shove in even deeper. Your head slides on in. You hear Kuu gasping like a virgin being deflowered, which, given the size of your head, would seem reasonable, except you have seen, and felt, her take in entire bodies without a qualm.
Kuu seems to be aware of your thoughts. "Feels tight, right? It makes for better stimulation. It's not going to get any tighter, but I can really close it down if I want. Five different boys think they popped my cherry."

You aren't really listening. Kuu really does taste better the further in you go, and so you are trying to shove in deeper. To your surprise, your shoulders squeeze in easily. Then you slide in to your mounds. Now you realize that even as you are stimulating Kuu, she is stimulating you. Amazingly so. That unknown lass who unbirthed you was good, but Kuu is showing you how it is really done. Probably all that is keeping you from fainting with joy is that Kuu wants her own pleasure and is willing to let you supply it.
She does climax first, but your nipples become rock hard as you explode hard enough to make you feel you cheated her on the exchange. Determinedly, you devote yourself to evening the balance.
You soon do so, but even as you do, you feel your next wave of emotion overcoming you. You are once again in her debt. Back to the fun game of paying your debts.
Now you realize Kuu has consumed you down to your hips and you get another demonstration of her talent as she is somehow able to get her lips in loving contact with yours. With your body jammed into her like this, you would have been sure your most sensitive area would have been out of her reach.
Obviously not. The two of you obtain a sweet simultaneous miracle which puts you even deeper in her debt. That is probably the only thing that keeps you active. You have got to push yourself the rest of the way into her to pay that debt.
Happily, Kuu is lying down, so this time you are not left dangling. Instead your feet finds things to push off of, which at the end include Kuu herself, a familiarity that gives her a final climax.
As you achieve your goal and cuddle into a ball, you find that you may have done all you can, but Kuu hasn’t. She is still stimulating you. Fortunately perhaps, rather gently, but you are amazed she can at all. “Very good for a first time” you hear Kuu say. “Now would you like a little introduction to motherhood? Or something else?