My girlfriend Beth had been sending me provocative pictures all day on my birthday. She told me, to hurry home from work because she had a special surprise for me. When I got home and we took a shower together. Beth gave me a back massage then I felt her finger enter my asshole. I got rock hard as she entered a second and then a third as she slowly massaged my asshole. She smacked my ass and said, "you're mine tonight," t...