One day while I was living with my girlfriend, her older sister 'Fuua' came to stay at our house for 7 days. She is tall and cute with long limbs, but the mature older sister doesn't look like her younger sister at all...She somehow accepts me and lets me in, and we have a relationship where we overlap with her body. To. Our cheating sexual intercourse flares up with a feeling of guilt. I'm hiding so my girlfriend won't find out