Hmm how do you find the one ending that has her with another woman inside of her....
Viewing post in Dating Cristina (Vore Game) comments
In case you mean the one with a POV of the girl inside her:
(Spoilers) Try getting her particulary hungry during the first date and the phone call. For example in the call you can offer youself to be eaten but back down. If you do, and you get her to drink a couple of times during the second date, before leaving the bar she will go to the bathroom and run into an old friend. From there just keep going.