He understands

"It's okay, Doe. I can't very well be mad about my son doing something I myself am. Plus I bet even if I asked you to stop fucking him, you wouldn't, right?"

Doe gave a small smile. "That you understand means a lot, Don. However, I am an adult and would keep seeing John. I like fucking him and want to continue to do so." You felt heartened by what she said. She then leaned down and gave your dad a deep kiss. "Of course that applies to you too. Even if John told me to stop fucking you, I wouldn't. I can't get enough of either of you."

"Does he know..about us?" Your dad asked after the kiss.

"Yes. He caught us that first night together," Doe admitted with glee, practically wettening anew at the memory.

You couldn't believe Doe was admitting all this. You both anxious and excited to see where this was going to lead.

"He did!? Shit..how did he react?"

"He thought it was so hot. He stood there watching us as you unloaded into my butt." Doe got this euphoric look on her face at the memory, her arms closing in, squeezing her breasts together. "God that was a great night. He fucked me right after we were done. He took my ass too. Having both of your cum inside my butt was the greatest feeling!"

Your dad looked shocked, but less than before as he was understanding Doe more and more. "You really are the horniest slut I've ever met."

Doe grinned. "You love it though."

You heard your dad give a chuckle before responding. "You're right, but could you do me a favor?"

"Sure, Don. What is it?"

"Could you not tell John I know? I don't want him to feel more awkward than he probably does already."

Doe nodded. "I think he'd be fine knowing, but I'll do it, Don."

She didn't have to tell you, you already knew. Essentially, you realized, she could keep the promise without really having to change anything she was doing.

"Don, I need to use the bathroom for a minute," she said, easing herself off your dad's dick.

"Sure, Doe. Don't hurry on my account." You slip the door shut, guessing Doe wants to talk to you.

She laughed warmly as she got off the bed. "I might hurry anyway. Talking about that night makes me want you plow my ass again!" She called back as she opened the door.