My sister rented me out to her female friend without a brother as a pretend brother! We took baths together, slept in the same futon... Basically, my role is to fulfill all the things her friend would want to do with a brother. But both of us are physically adults... and in the bath or while sleeping together, I inevitably get really aroused! But my sister's friend seems to find even that endearing, and we're crossing the line, with what was supposed to be just a one-night, two-day arrangement now looking like it might be extended! Honestly, she's a hundred times better than my real sister! She's kind, and erotic...
