My mother-in-law saw my dick go up her daughter's ass.

We were spending the weekend at the Algarve apartment, and Sandra invited her parents to join us, and Sandra's parents have no idea that we're a liberal couple and her daughter is a sex maniac, and usually when we're in her presence, we try to be a normal couple.
The apartment in the Algarve has only one room and as a matter of politeness, it was the older couple who moved in.
The living room has a very comfortable sofa bed and it costs nothing to sleep on it.
The first night we didn't have sex because as I've reported in previous stories Sandra moans a lot and sometimes screams loudly when she comes.
On the second night, I waited until dawn to fuck. Sandra didn't want to, but she couldn't resist my advances when I started to pass my hand through her body, taking longer in the intimate parts. It was hot, but we didn't take the sheet off for fear of one of my in-laws leaving the room to go to the kitchen or the toilet.
Under the sheet, I went down and my mouth stopped on my wife's smooth pussy. It was very wet and tasty. I turned my panties to the side and licked and played with the clitoris which made her groan softly. I stuck my tongue down and she groaned more. Then, in the position of Mom and Dad, I inserted my cock to the bottom. She covered her mouth to contain the groans. We fucked like this until the first orgasm. Sandra came with her hand covering her mouth and the orgasm was contained. We switched positions and now, naked, I was down and over. This must be the position she feels the most pleasure. It was very hot and with the movements, the heel stopped covering us. She climbed down on my dick and followed hard as a little and Sandra's face was above the window open, to see the whore's face increased when we thought we could be safe from the groans and the pleasure we had never seen before.
At one point I saw a bullet going towards the bathroom. It was my mother-in-law's saint. I increased the stitches and Sandra moaned more, because I had no idea what was going on. I was excited to think that the old woman had heard the moans and I decided to do something worse when the bathroom door opened, I got out of the crib and got in the ass all at once.
- Oh, my ass.
Sandra groaned, and I'm sure her mother heard her, because I saw her stop and look at us before she turned off the light, and as the bathroom door opened, I'm sure she saw my dick go up her daughter's ass.
That's right, fuck me, I'm going to turn around.
Sandra came again while her mother was going to the room. That excited me very much and I saw myself also in her bowels. The excitement was so great that I gushed rivers of sperm inside her.
- What a delicious ass.
After I saw myself, my dick got hard again, and I kept pumping, and I took it out of my ass and put it back in my pussy.
- What's with the hard-on?
It's you, my little whore.
It exploded and we saw each other together with her usual screams.
Then we rested and she asked.
What's all the excitement about?
- You'll be mad at me if I tell you.
- It counts.
I told her, and she wasn't upset.
- You think he saw your dick go up my ass?
At least she heard you ask her to fuck you.
She can do the same thing to Daddy.
At breakfast, they barely spoke with shame, but with the passage of the day everything went back to normal and when the night came I fucked Sandra again with the wish that this time it was the father-in-law going to the toilet, but it did not happen.