Check out my Literotica work; I just finished chapter 7. For the most part, the site archives past relationships...straight, bi and gay. Let me know what you think.  
https://www.literotica.com/s/rob-robin-and-darin-ch-01  
https://www.literotica.com/s/rob-robin-and-darin-ch-02 
https://www.literotica.com/s/rob-robin-and-darin-ch-03  
https://www.literotica.com/s/rob-robin-and-darin-ch-04  
https://www.literotica.com/s/rob-robin-and-darin-ch-05  
https://www.literotica.com/s/rob-robin-and-darin-ch-06  
https://www.literotica.com/s/rob-robin-and-darin-ch-07   
An excerpt from chapter 7, using Robin and Darin:   Heavy and rock-hard in my hand, I gripped the base and swatted his cheeks...then hers. As I rubbed it over her nose, she tipped her head and savored the thick shaft with her tongue. I lifted her head back further so she could work the thick, purple head...then I pushed forward to stretch her lips open.  
Gently pumping till I felt the back of her throat, I held it there, until I felt her moan for more. I didn't hesitate to begin sliding her throat, up and down, over my dick. I was stroking my cock with her face, "Fuck...fuck...Robin...Robin...yeah...yeah...yeah...take it...take it all! Fucking...fucking your face...fuckin' it like pussy...just like pussy...oh fuck...a tight pussy...fuck!" I bunched her hair to get a better hold and humped forward, her to take it all. I looked down at the fistful of hair; the brown curls tumbled through my fingers and cascaded down around her face. As her head bobbed, she gurgled a little, but I just kept pumping it back in...shoving deep.  
Eventually, I pulled out and used Darin again, "Suck it...suck that dick...suck it...yeah...yeah...yeah...uhhhh...uhhhh...like that...just like that...fuck...fuckin'...suck me...suck that dick!"  
Then back to Robin...but I pushed into her cunt, "Let me in that pussy...that's...that's good...yeah...uhhhh...uhhhh...tight fuckin' pussy! Mmmmmmmm, that's sweet...yeah...uhhhh...uhhhh...uhhhh...yeah...yeah!" 
"Rob...Rob...fuck me...fuck me...use that...fuckin' use that pussy...use it...it's yours...uhhhh...uhhhh...all yours...yeah...yeah...fuck me...fuck me...good...fuck me good."  
"Mmmmm...I'm gonna get it all wet and use your throat, again...uhhhh...uhhhh...get me wet, sweetie...yeah, get me juicy wet"  
I moved around to fuck her mouth, "Yeah, taste that pussy...taste your pussy...yeah, baby girl...yeah, that's it...taste that pussy...lick it all off...yeah...yeah...suck that dick...suck it! Gimme that throat, again...yeah...yeah...yeah...that's it...uhhhh...uhhhh...uhhhh!" I went crazy, slamming through her lips and down her throat. She wanted to be used and I thrust, over and over, rapidly nearing my limit. To stall release, I finally had to pull out and shake it off; precum and spit dropped into the straw, on the floor.  
Another bead glistened at the very tip of the long, throbbing dick...it was a picture...a fucking pornstar cock, ready for the next scene. While I pushed things back, I stroked with the spit and admired Darin's ass. It was hot...a perfectly rounded, male ass...firmly muscled and well-defined...it was perfect. I stroked on lube, again, "It's your turn, dude...ready to be used?"  
I caught his grin, "Born ready...fuckin' born ready...use me."  
I moved closer, spread his cheeks and playfully swatted him; repeatedly, I brought my hand down hard over the firm flesh. His right cheek was turning pink, but he didn't care...pleasure was the only thing that mattered. He looked back with a big, sexy smile and moaned, as I poked the head inside. Humping forward to split his cheeks, I pushed deep into his belly.  
Turned-on from the intense pleasure of welcoming another man's cock, he groaned, "Fuckkkkk...Rob...that's fuckin...mmmmm...mmmmm...perfect...uhhhh...uhhhh...uhhhh...perfect...perfect!"  
Yearning to have a dick stretching his insides, he tried to push back, only to discover he was tied and couldn't. I kept pumping, while he begged, "Mmmmmm...yeah...yeah...fuck...fuck...you gotta fuck me, dude...fuck me...fuck me hard! I need hard fucking...fuck me...yeah...yeah...yeah...fuck me...fuck me!"  
I grabbed hold of his waist and started pumping harder. His muscled ring was stretched tight and rippling over my dick, sending sensory ecstasy through both of us. Time and time again, five...six...even seven inches emerged, only to plow right back into his gut. With my hips slamming his ass, his cheeks bounced, and his moans grew in intensity. He kept begging, "Fuck yeah... fuck harder...uhhhh...uhhhh...uhhhh...fuck me...fuck me...uhhhh...uhhhh...uhhhh...uhhhh...fuck me, harder...harder...yesssssssss...yesssssss!"  
Fucking and churning his insides, my dick raged with a need for release and I had to pull out, again. I quickly beat things back and moved back to my girlfriend...she needed attention, too. Her inner lips, glistening with musk, looked puffy and ripe for cock.  
Shudders ran through her body, when I teased the lips. She was patient while I fucked Darin, but now she was aching for it...her pussy needed it bad. She knew she was going to get both of us that afternoon, and the thought of two hard cocks taking turns, had her dripping wet.  
Pushing forward and parting the lips, I had her moaning, "Ooooh...ooooh...god, that's it, sweetie...that's it...yeah...yeah...yeah...take that pussy...take that pussy!"  
I smirked, "I know you want it...you want it, don't you?"  
Her lips spread wide to accommodate the girth and she moaned into the rafters, "Oh god, Rob...yes...god yes...I want it...want it all!"  
Leaning over to grip her shoulders, I pumped deeper and groaned, "Fuck...sweetie...fuck you're tight...mmmmm...uhhhh...uhhhh...uhhhh...fuck! Mmmmm...there you go...that's what you want...big, hard dick filling yer pussy...yer tight...tight pussy!"  
"You need a little spanking? I think my baby girl could use a spanking." She cried out as hard, rhythmic strokes, fell over her ass; they stung, but she never wanted me to stop. She moaned even louder, when my fingers found her clit, "Fuck...fuck...yeah...yeah...Rob, that's so...so fucking good...mmmmm...yeah...yeah!" She had moistened the inside of her thighs and my swats reverberated through her body. I always loved the feel of her wetness...a woman's arousal was erotic and crazy satisfying.  
I held tight and drilled her pussy, till she was completely exhausted and out of breath. My gaze fell on the tight pussy, working my dick; the puffy lips gripped my thrusting cock, just like a tiny mouth.  
"Yeah...yeah...that's it...take my cock, baby girl...take it...take it!"