Clean her, dress her, take her home

You can't just leave her like this. You grab anything you can find that will work as a towel and wipe the thick cum off Tori's exquisite body. You hope whoever's room this is doesn't mind that most of their possessions now have Derek's jizz on them. You get Tori dressed as best as you can, and then carry her out of the house and into your car. You take her back to your place and let her sleep in your bed while you take the couch. Your asleep the minute you lay down.

You wake up and get ready for a new day. Tori is still asleep so you try to be quiet while getting dressed. You prepare a pot of coffee and wait for her to wake up. When she finally does, she looks disoriented and hungover. 2 things you expected. You learn through talking with her that she doesn't really remember much from the previous night. She does, however, reciprocate your feelings. She's willing to give a relationship a shot. You are of course thrilled, but you cannot get the sex she had with Derek out of your mind. You wonder if you should tell her, but decide on keeping it from her for now, instead claiming that Derek bailed on her when she got too drunk and she called you to get her. She believes you, even if the story is lacking any real evidence.