Quite frankly, she sounds like a manipulative narcissus. I have a sister who is a N and that sounds like a move she would make. Offer that "drink" all smiles and such with the hidden poison inside and the knife raised and ready to plunge into your back once she's got you in her grips. If your hinky meter's going off with her, LISTEN to it. I learned to trust my hinky meter with my sister and finally went NC and have never looked back.