My girlfriend's big-breasted younger sister, who is innocent and seems like she would definitely let me have sex with her, missed the last train and came to stay the night.

I received a sudden call late on Saturday night. ``I missed the last train, so please let me stay the night.'' It was from her younger sister's sadness. I thought I'd declined, but a few minutes later the doorbell rang. Then he comes into the house without permission. It seems like there was alcohol involved, so they were closer than usual and there was a lot of body touching. Moreover, the chest is loose... He presses his chest against my chest as if he's inviting me on purpose. What will you do if she finds out... "I guess I'm right." "Hmm? I'm guessing this. On purpose." Oh, I might be crazy.