When it all happened I was at my dad's place. It was a Sunday morning and I knew that after all the partying my dad wouldn't be up till the late noon. I was horny and wasn't right in the head - so I had a brilliant idea to watch porn on the big screen in the living room. Now, back when I was a kid I used to jerk off using plush toys. My favorite was this big plush turtle and he was my partner in crime that day.
Long story short - my dad woke up early and saw me watching Playmate compilation with the plush turtle between my legs. He just silently walked off and I rushed to my room. Some time later he called me for breakfast and everything seemed normal. He'd never mentioned this incident, ever. I even started to think that maybe he'd been hangover that morning and hadn't actually remembered anything.

Years later (I was in my early 20s) me, my mom and dad went out together. My mom got nostalgic and started reminiscing about my childhood. And of course she had to mention that god forsaken turtle and how I loved it and always slept with it. " No wonder it got so ragged!"
One look at my dad's grin - and I realized he clearly remembered everything from that day.