Billie and Brutus's first time

I met Billie on the enter net, his's a transgender who lives as a women, she asked me if I knew she was a man, I said of course I did, we emailed for awhile,then text and we decided to meet, I'm a big guy, smooth masculine shaved Pearced 8"dick 250lbs, she's Pettitte,long black hair, smooth, small breasts,average dick,tight manpussy,I fucked her, we hit it off pretty good, I injoy being fisted, she injoyed fisting me too.
She told me about secret fantasies and I told her about Blue fucking me and how much I injoyed it.
She told me she has wanted to try getting fucked by a dog but never had the opportunity to do it.
We kinda left it at that,I didn't tell her I had another great dane, his name is Brutus,
A couple days later Brutus was knotted in my ass, I took a pic of it and texted it to him, I got a response back immediately I want to be there with you next time time he fucks you
I texted her back saying Saturday morning would be ok.
She showed up and Brutus didn't take to her at first.
He didn't like her sucking on my dick or me fucking her ether.
I got him to lay on the floor and started rubbing his dick, it started coming out and getting bigger.
I start stroking it, licking the length of it,I get Billie to take my place, she starts deep throating him, I lay next to Brutus to let him know I wasn't doing it. He licks my shoulder, Billie makes him come, I fuck Billie's ass again and fill her full of my come.
Brutus tries to mount her and knocks her to the floor, I get a small padded bench and make Billie lay on it, it's perfect, Brutus mounts her and his humping her, I aim his dick to wards his ass hole and he rams in, Billie screams, and tries to get away from him, his got his front legs around her and she's not getting away,his hammering into her pussy and all my come is making it easier for him.
His knot is ready to go in, she screams no don't let him do that, I was too slow, he pulled back and rammed it into her, he really starts fucking her now,his knot is locked inside her now and it's bulging out her lips.
Brutus slows his pace and stops, he hops off her and now butt to butt with her,I take hold of Brutus's collar to keep him from dragging her around.
I can see Billie's belly bulge from all the come his pumping into her, it's starting to squirt out around his knot.
Billie asked when will he be done, I tell her about 15-30mins, depending on how horny he is and how long you want him in you, you can squeeze your pussy musules and make him stay hard in you longer.
Brutus knot starts getting smaller and he pulled out of Billie, it makes a popping sound and come gushes out Billie's pussy, Billie sighs and says that's the best I've ever been fucked before, I got a little jealous about that.
But I knew I couldn't compete with Brutus.
When Brutus knows Billie is outside the house he gets very excited because he's going to breed his gurl again.
He goes to her house for the weekend sometimes while I'm away.
They're best friends or should I say close lovers now.