Well, first things first, I'm a fat bi guy in my late 40's, my bi boyfriend is a couple of years younger than me and he's a skinny guy to boot. We're both naturists, and so are most of my "in-laws". His dad is also bi, and my confession is that I mistook my bf's cock for his once. I mean, it was a simple mistake to make at the time. You know when you're underneath a table with a big table cloth that makes it a lot darker, and there's more than a couple of cocks in front of you. This happened at a barbecue with my bf, his dad, and some other guys, that I knew were either gay, bi or straight but gay on the D.L. But that's cool with me, either way. Anyhoo.
And as I was under the table I saw what I thought was my bfs cock. As they're similar in size, I didn't think of it.
And so, I started gently rubbing it, before I kissed it and to suck him.
He didn't move an inch while I was sucking him. I used my tongue to make him cum quickly. And when he came, he locked my head between his legs so I couldn't move. That made me swallow everything. Not that I minded a bit. I love semen, mine and my bf.
And afterwards he just let go. As I emerged from the table, my bf's dad got up and approached me.
My bf had no clue what had just happened. My bf's dad took me aside.
And told me that I had sucked him instead of his son. Now, he didn't mind that, as he told me that he thought I was pretty good.
But I should tell my bf about what had just happened.
I nudged my boyfriend over and told him then and there. I thought he was going to dump me then and there, but he didn't.
In fact, he said that if I wanted to, he was more than willing to share me with his dad. He knew that his dad had been single for a while.
He asked his dad if he wanted to hook with me, he could but he wanted to watch.
I thought that sounded kinky, so I liked the idea. It's not like it was my first rodeo. Lol.
His dad looked at me and slapped my fat ass so loud, that he got everyone's attention. It didn't hurt or anything but the amount of attention was unusual.
One old guy looked at me. He yelled to my bf's dad, let's call my bf's dad Andrew: Hey, Andy, so you're gonna do him?
And without even as much as a warning or hint of embarrassment, he said, smiling: Yeah, I intend to fuck him so hard he won't be walking properly for a day!
The old guy quipped back: Well, if anyone can do that, it's you.
That got the whole party laughing.
But the old guy wasn't finished.
You should do him here.
My bf's dad looked at the old guy: I think that would not be a good idea. Gil, give him another beer.
He then took me by the hand and told me to go to his bedroom and then weight for him, as long as it was cool with me, with both of us. My boyfriend told me that it was cool with him.
And so, I went to his bedroom and waited.
Shortly after, my bfs dad came.
He commanded me get in bed. I had never really had any thoughts about kissing him, but I just went with it.
As we were making out, he put some
lubricant on his hands and started to massage me. He commanded me to lay on my stomach and just relax, which I did.
When he drove his fingers into me, I thought I just died and went to heaven.
But that was nothing, compared to what came next. After he was done fingering me, I could tell he was horny.
He applied some lubricant to his cock and gently spread my legs and teased my hole a little bit before he drove it in.
And he wasn't kidding. At first, he was gentle ish and as he got harder and harder, he fucked me harder and harder. I was completely awed by him.
My bf was good in bed, but not like this.
And my bf's dad was true to his word, he fucked me so hard, I literally couldn't walk properly for a couple of days.
When my bf came to the bedroom, he asked if I was up for round two, which I was.
By the time he was done, I was also done.
I managed to get out of bed and walked while leaning to the wall.
When I got outside, the party had died down a bit, but the old guy was still there.
He asked me: Looks like he fucked you real well. Did you like it?
I replied: Hell yeah! I'd gladly do it again.
Then the old guy grabbed my nuts gently, and said: Welcome to the family.

I never did anything with the old guy, except let him fondle me occasionally. He turned out to be a ex of my bf's dad.
Thanks to my bf and his dad, I've had plenty of threesomes.
This arrangement has been going on now for the past four years. I love it!