I had walked in on my stepmom masturbating more times than I could count, but this time was different. She was on the edge of the bed, legs spread wide, fingers buried in her dripping pussy. Her tits bounced with each thrust, her moans filling the room. She was lost in her pleasure, not noticing me until I was right behind her. I could see her juices glistening on her fingers, hear her ragged breathing. She looked back at me, her eyes wild with desire, and whispered, "Join me."