You take a deep breath and say: "Now, for your transform, every time you lie to me, you will transform into a live like sex doll that can feel and enjoy everything. And you will stay that way untill I have cum inside you. After that, you will turn back."
Your girlfriend looks at you openmouthed, she seems a little angry, grabs a pillow "What? I never ever lied to you!" She shouts, and slumps the pillow at you. Of course you duck and answer, that this is exactly, why you chose that transformation. Your girlfriend stays suspiciously silent. As you raise your head, in her place, you find a very live like doll, sitting upright, her face showing a perfect ahegao, her eyes tilted, her mouth open and round with her tongue reaching out greedily. She still looks as beautiful as your girlfriend and even though, you are shocked a little that this game really works, you are also really turned on, seeing, what power you have over her.
"So... you have lied to me.", you say, looking her in her eyes. "Maybe I should keep you this way..." And with that, your fingers start caressing her between her legs and your other hand starts rubbing her breasts.
You...