...Tiffany, the head of your high-school's cheerleading squad.
Normally, this is a type of girl who wouldn't even give a video-game playing nerd like you her time of day, but now she was down on her knees, her beautiful green eyes filled with lust, and her small hand, tipped with shining pink nail polish, delicately rubbing off your dick.
Slowly, she started sucking you off with her luscious lips, covered in red lipstick. She grabbed your thighs with both hands, and then deepthroated you, to which you reacted with a loud moan, and grabbed her hair- which was now waist long, platinum blonde, and branded to a high ponytail with a blue ribbon which matched her glittery cheerleading uniform.
She pulled her head back, parting with your dick, saliva dripping from her mouth. Then, raising her glance and looking you in the eyes hungrily, she commented in a high-pitched voice with a distinct valley-girl accent: "O-M-G, your sis should have totes let me know that you had such a yummy co-", upon which you released your semen, covering the face of the most popular girl in school with your sperm.
"Even your cum is, like, super tasty", replied "Tiffany", cleaning her face with a towel she found nearby.
"This was so hot, babe. I couldn't tell you apart from the real deal! Nice freaking choice.", you exhaled as you sat down on the sofa you were gaming on moments before.
"Thanks, hon! I had a pretty good time myself..." your shapeshifting girlfriend's original voice left the head cheerleader's lips as she twirled with her hair femininely, "So... what now?"