You decided to alter Vicky's drawer.
You had a bit of a foot fetish, and while Vicky was accommodating, she wasn't into it like you were. But not anymore. You peek through her files... sexual fetishes would be an easy one to alter.
Then suddenly you stop at the physical folder again. You wondered if you could change where she felt orgasms from vaginal intercourse to having her feet played with or stroked or kissed. You riffled through the folder and quickly found your two targets.
You pulled out the ability to orgasm from Vicky's vagina and clit folder. Now she would no longer feel any sexual pleasure from that. And you quickly put it into (Sarah's old) foot folder. Now she would get orgasmic pleasure from foot stimulation.
Happy with your modifications you close the drawer.
You go out to the bed and sit next to your girlfriend. Sarah's cute feet are attached to the end of her legs now. You reach out and stroke her sole. Vicky suddenly began to moan in her sleep. You stroked it again, and she let out an audible gasp.
"Wow, she's so sensitive now." You mutter.
Your stroking caused her eyes to flutter open.
"Oh, hey, did I nod off?" She asked, sitting up.
"Yeah, no worries. Do you want to go to bed?" You ask.