Cum to change

"Now for your transformation, when we both have sex with each other, you will begin to transform yourself when I'm cumming inside you." you answered.

"Oh my goodness, that's really kinky, hun. Also I like what you thinking about it." your girlfriend smiles and surprises when she heard your answer. "And by the way, was it better than Truth or Dare game?"

"I don't know, babe. This kind of game is really weird and it's hard for me to think too." you answered as you're scratching your head. "And I'm also thinking about sex when we play the game."

"Geez, you're such a horn dog, honey." your girlfriend replied as she's teasing you. "And I'm not the only one who feel so horny when you're not around, I've been masturbated a lot when I keeps thinking about you, so when you're saying this. That turns me on also."

When she finished her sentence, she starts to kiss you deeply and passionately. Soon, you let go of your kiss and began to strip off all of your clothes until you both naked, before going back to kissing. Then you both stopped and looked to each other bodies in naked and were ready to take it to the next level. Your girlfriend take a look to your hard cock which was tend high, ready for some action.

“My…” she said with lust in her voice, “Looks like someone is ready for me.” with that she was about ready to put your cock into her vagina. Once it's ready, she leans back onto your cock taking the whole thing in as both of you gasp at the feeling. After settling a little, she begins to move up and down rhythmically. Soon after this she speeds up more, bringing you to move your hips with her. As your both start to feel a building feeling, you sit up and grab her hips making her go even faster. With the newfound speed, your girlfriend finally hits the spot and forces you deep inside of her where you finally explode. You hold her tightly against you and kiss her gently as you continue to release your seed deep inside your girlfriend.

Both of you exhausted and falling into floor, you saw her skin is actually started to shift strangely. So the game was real along, and like you just said, if you actually cumming inside her, she will be transforms in just a sec.