This afternoon I stopped by the in-laws to retrieve some tools I had left in the garage. There was an unfamiliar car in the drive so I walked up to the house. I let myself in and could immediately hear noises from down the hall that definitely sounded like sex. Wow, I thought, the old bastard has a babe on the side. Curious as hell I crept down the hallway and peeked in the open bedroom door. I caught them as Dad pulled his big dick out of the neighbor boys mouth and told him to get on the bed. I spun back down the hallway utterly shocked at what I had seen. I took another look and witnessed Dad mounting that young boy. He drove his cock deep into his tight young ass and I got hard watching. I masturbated in the hallway and nearly fainted cumming when Dad blew his load in Tommy's ass. I got my own ass out of there before I was discovered, excited at future possibilities.