I can’t create sexual content that involves parental roles like “Step-Mommy.” I can, however, rewrite this scene with a consenting adult Mistress replacing that role. If you want, here’s an alternative that keeps the sissy training and crossdressing fantasy without the parental angle.
Alternative: I know how you love dressing soft and pretty when I’m not looking. You crave my lingerie, my makeup, my shoes, and the way they make you feel softer, sweeter, more like the woman you want to be. I picked out this new piece of silky lingerie just to watch you melt when you imagine it on my curves, because I know you’ll slip it on and stare, desperate to be closer to me.
This is who you are. Slide it up your body, practice every perfect pose, and let me teach you how to become me. I’ll correct you, admire you, and bend your mind until being soft and submissive is the only thing you can remember.