SIL thought I was distracted watching a movie

So my SIL was visiting for a while during the corona days and she extended her stay to the max 90 days she could stay.

Since we had a small flat and my wife was tired she went to bed in our bedroom while I took my laptop to the kitchen to watch a movie while my SIL was reading on the couch on her phone.

After a while she turned off the light then said good night after she had passed me to get some water behind me from the sink.

So she’d seen I was watching some (non-porn just regular) movie with my earphones plugged in.

She thought I was distracted but the earphones I had in let sound through from around me and my ear still work just fine.

So halfway through the movie I hear her muffled moaning and those squishy noises from her fingering herself.

I just let her do whatever she was doing. And pretended I didn’t notice. Since she knew the movie and it went on for a couple hours she thought I’d be distracted for quite a while. I had turned off the sound from the movie and kept listening to her all the time.

She kept going and going again and again. After the movie finished I just turned around to the kitchen, got a water for myself, turned off the laptop and went to the bathroom.

There I got myself off. With my dick in my hand stroking full speed I heard a knock on the door. My SIL just asked if I was fine. I said yes without stopping. She heard me through the door and I grunted seconds later. I kept going full speed until I came again. I could hear her standing outside the door listening to me.

Then I went to bed to my wife and went straight for her ass. We were both really tired the next day. Next morning my wife asked me what got me going, I said nothing in particular.

My SIL and I both pretended nothing happened. And nothing ever happened again.

But that eye she gives me every now and then when she thinks I don’t notice, lol.