Sam And I

After we put all the stuff up and Sam went home, we were eating dinner in silence again. My dad looked from me to his plate. "So what did you and Sam do?" He asked, and I smiled happily.
"Sam and I fucked!" I smiled, and they looked at me like I killed someone. "What?" I asked, and my dad looked at me seriously.
"Randy, that's not a good word and what do you mean by that?" He asked, and I looked from him to my mom.
"Well Sam and I were in my room on my bed, and he put his penis into my butt-" My mom squealed, covering her ears. "Don't worry! We used a condom!" My dad jerked me up by my arm and pulled me onto the couch, pulling my pants off and taking off his belt. Oh no! Not a whipping! He smacked my a*s harder and harder until I started to cry. Then, he sent me to bed without really eating dinner.
What did I do wrong? It seemed okay to do that. The adults were doing that on the t.v. It felt really good too. Did my parents not want me to do that? Why? Did they not want me to be able to feel that?