One night, my super serious sister came home drunk, but she came to my room and started talking dirty! She took off her clothes and exposed her underwear! She rubbed her breasts against me, took off her pants, and went wild with lewdness! I had no choice but to let her sleep in my bed... When I woke up in the morning, she seemed to have no memory of it at all! Why!? Naked!? My sister was so cute and fidgety and embarrassed that I got an erection! And then she noticed my erection and had sex with me...!