Saw my mum fuxking my uncle

I (25) Saw my mother(50) fucking her brother(48). And now we both fuck her.

A little bit of backstory.
I never knew my dad since he left me and my mother when i was 2.
My mother and her brother were having sex in their younger years and still did it on and off.

I grew up normally. I was never interested in incest.
When I was 19 my uncle came around for a couple of days since he lives in Spain and is married. He stayed at ours and I always liked my uncle like a big brother figure.

One night I wake up to go to the bathroom. I could see the living room lights on from the top of the stairs. I assumed they were watching a movie or something. I went to have a quick look from the top of the stairs and I see my mum riding my uncle both naked. I quickly jolted back with shock and walked quietly in my room, I was completely shocked and trembling at first.

I pretended nothing happened around them but still felt unnerving if that makes sense.
Months later, I couldn't shake the image out of my head. I always thought that my mother is an attractive woman with a fine body but never thought of her sexually. But I slowly thought about her more and more and started to fantasise about fuxking her.

About a year later. I gathered enough courage to confront them about this. But I would ask my uncle first since I trust him more and know he would be completely cool about this.
I went to visit him in Spain for a couple of days. He took me in his boat to ride around in and have drinks. I told him that I have to tell you something. He asked what it is and told him that I know about you and my mum because I saw you guys doing it on the sofa once.
His face went pale because he thought that this was bad. But I told him straight away that I am completely OK with it and think that it's pretty awesome.
He looked at me realising that it was not the outcome he was expecting. He laughed and said boy you have no idea how fast my heart is pounding. We both laughed. I asked him "I don't want this to sound weird but do you think I have a chance?" He smiled at me and says "she has been waiting for this for a long time" he tells me that my mother has also fantasised about me. I wasn't expecting that at the time. I never knew she thought of me that way.
I asked my uncle what would be the best way to approach this without being weird or obvious? We came up with that if I get her drunk on gin and tonic she gets wild, and that she always wanted to do a threesome, she really likes to read and hear stories about threesomes. So I had to think of a way to share a made up story of me in a threesome infront of my mum when she is drunk.

Couple of months later we are back in Spain. There was a party full of English hippies and me and my mum were there.
It got to about midnight and there was 4 of us in a jacuzzi. Me, my mum and 2 other ladies my mum knew.
I saw that my mum was drunk so I knew if I had an opportunity this would be the one.
I somehow manage to direct the conversation about sexual stuff without sounding too weird. One of the women in the jacuzzi was wild in the sense she did not care about anything or talking about sexual stuff. She tells a story about her and her husband one night about them fucking like crazy etc etc (I don't remember the story) the wild lady joked around with me teasing my mum "look at your handsome boy! I bet he has all the ladies on her knees!" I gathered the courage and said "well I have done a few threesomes so I must be doing something right lol" they were laughing but my mum looked at me with the expression of is that right now? kind of face

After a while I realised it was not going anywhere. We all went back to our rooms. I was in bed with my phone getting ready to masturbate, I was getting hard and was searching for a porn video on my phone till suddenly I hear a knock on my door and it was my mum. I quickly covered myself with the blanket and pillow before she entered. She asked me if i was OK and needed anything like water or something. I told her that no im OK. I could tell she was still drunk because she still had her bikini on and she was wobbly. She looks at me and says "why did you never tell me you did a threesome?" I smiled at her and told her "why would I say that kind of thing to my mother?" She laughs and agrees. She sits on the edge of my bed and realises that I had my pillow over my groin. She just goes "oh for fuck sake Bullydog(I'm not going to reveal my name so just my author name). I just smiled looking guilty and said "you did just walk in you know lol"
Her face had a devious look about it, something that I've never seen before. My heart was pounding.
She gets up and says "Well I'll leave you to it because I don't think want me around" she walks towards the door but I tell her that "well I was gonna google milf in a bikini porn lol" in a jokingly way. She turns around with a shocked but smiling face.

At that moment I thought fuck it and lifted the pillow to reveal the outline and shape of my hard on. I'm not a person that Bragg's about it but I am pleased in the penis department. Her eyes opened up after realising the size. I put my hand down under the cover to stroke it "so, are you gonna leave or are you staying? I can still look for porn if you are going"

At that point she slowly walks towards me while she takes her bikini off. When I saw my mums pussy I was in disbelief. Better then I ever imagined, it looked tight and young. She gets on top of me grinding on my dick. Her face was kissing distance to mine. She whispers "is this what you wanted?" I put my hands on her hips grabbing her tightly and kissed her.

I never imagined my mother being so wild.
We were fucking in the cowgirl position for ages. She gets up to suck me off for a while, after 2 minutes she tells me to get up, she gets on her fours presenting me her round ass. I fuck her in the pussy for a good and rough 5 minutes while I'm pulling her hair. I stop for 5 seconds to catch a breath and she tells me "I was hoping you would use the other hole" somehow she sparked me with energy and I gently stick it up there slowly getting rougher. After hearing my mum moan I finished.

After that happened, my life has been crazy.
Sorry for the grammar mistakes. If you have any questions let me know.