Down her mouth

Noticing her cup of coffee, you hatched a devious plan to enter Kim's body. Silently and slowly, you slithered on her floor, making your way to her cup of coffee. You patiently waited until she set it down somewhere, then you jumped into the cup. Despite the hot temperature, you don't feel being burned. Being a goo apparently makes you much more resistant to temperature. Weird.

Suddenly, your sister picked up the cup you're in and she drank from it, unknowingly gulping you down. You watched as you went down her throat and into her stomach, your vision darkening until...

You opened your eyes and you see your sister's room right in front of you, as well as the cup of coffee you were now holding in your hands. It worked, you are now inside of Kim's body!