"Well, why don't we put the console down and get some business?" You reply as you lean toward your shapeshifting girlfriend who is now currently a 10-year-old boy. "Look, babe. I know it's wrong, but I'm not trying to be weird... It's just that I want to try something while in the form you're a little boy. After this, maybe we -"
"It's okay, hun. Relax, I know what you're talking about." Your shapeshifting girlfriend replies. "Don't worry, I'm not upset or anything."
"Phew,... thank god." You relieve.
"Anyway, let me remove all my clothes first," your shapeshifting girlfriend in 10-year-old boy's form uses her/his ability to make entire clothes vanished without a trace, leaving him/her youthful naked body. "So, would you like to take this little boy to your room?"
With that cute look and attitude that your girlfriend flirts with you as a 10-year-old boy, you take advantage of his relatively light weight to pick him up and carry him to your bedroom. Once you're there, you gently put him down to the bed and kiss him. Even if the little boy is technically just your shapeshifting girlfriend who she morphs into, it still feels so weird to make out with him/her. But it doesn't matter. He's still the same girl you loved. S/He can't stop you (not that he wants you to stop) because it feels so good. S/He moaned in, seeming confused pleasure with your tongue thoroughly exploring his/her mouth. His hairless legs curled around your waist. A strand of saliva lingered as your lips parted from his panting mouth. His adorable face was flushed red, and his eyes gazed half lidded up at you. "How was it?" You break the silence.
"Teehee,... it's a bit weird and too sensitive with this little body, but it's alright, I'll get used to it." Your shapeshifting girlfriend in 10-year-old boy's form answers and breathes.
"If you say so, babe. Besides, you're very cute in this body, even if you're a boy." You smile as you still pin the little boy's arms above his head. You go to nipple on his right nipple while your free hand plays with his left. To your surprise, your girlfriend or this little boy reacted far more to the nipple play than the tickling. Wow, is he really that sensitive?
"Ah! Ah! Aaah! That feels...! Oh! Mmm... Oooh. Easy there, please, slow down... Aah!" You do not want to slow down, though. Nibbling, pinching, licking, flicking, circling, sucking... You play the moaning boy like an instrument until his quivering pleading becomes incomprehensible, babble.
Sticking your fingers into his mouth and making his suckle on them, you use her/his saliva as lube as you begin to finger him, opening his hole one finger at a time. Now you were just far too turned on to second guess yourself.
Now, he's finally ready. You let go of his pinned arms and use both hands to grip his hips. She or he's no longer trying to hold back, but just twitching and drooling as if you've already broken his mind.
A twinge of awareness returns to his eyes as the tip of your lubed up cock finds the brats quivering hole. "Honey... t... take a easy on me..." The boy whimpers, half in fear, half in need. You shove into him, and he throws his head back and moans. One long passionate moan as you slowly push deeper and deeper and deeper into your transformed girlfriend.
Finally, all the way in, you look down at the gasping little boy beneath you. You can't believe how tiny his body is cimpated to yours. Yet you're inside him. Her? You don't care anymore. You pound away, holding the little boy by the hips and thrusting as fast as you can. He cries out, clutching the bedding like a life raft. He's so tight as the bed rocks as if on a turbulent sea.
You raise his hips so his knees are next to his head, and you're pounding him directly down into the bed from above.
"H... honey!" Your girlfriend/the 10-year-old boy cries out after ten minutes of relentless fucking. "I think I'm about to... come...! I... cum...!" Sweat dripping from your chin, you pick up even more pace and time you orgasms to sink up. You fill the brats ass as he let's out a stream of cum all over his own face.
Panting, you lie down next to you girlfriend and watch his cum covered face. You could get used to your girlfriend looking like this. After the orgasm, you take the box of tissues and clean your girlfriend/little boy's face and body from his cum. After you finish cleaning him/her up, you both give each other a kiss on the lips. "So, what do you think?" Your shapeshifting girlfriend/boy asks.
"It was strange and weird, but it feels great." You reply. "And no matter who you turned into, I still love you, babe."
"I love you too." You both then continue the kiss as you make out with him or her. Later, s/he breaks the kiss and asks. "So, what shall we do next?"