I saw a stain on my best friend's girlfriend's panties while she was sleeping, so I secretly touched the stain with my fingers. I was so excited by the sticky mucus that was dripping and the sight of her big breasts in a mess that I couldn't hold back! I know I shouldn't touch her, but I can't help it. Gradually, her crotch, which was supposed to be asleep, started to get so wet that it couldn't be contained in her panties...