Open relationship turned into cucking [cuckold]

So I’ll start by giving some details about mine (Paul 21) and my girlfriend’s (Tiff 24) relationship. I’m 5’7” 150 lbs and tiff is about 5’3” and maybe 140ish lbs. Tiff is a thicker girl, not fat, she has a BIG butt for a white girl. You would think she was Latino from behind except she is pale skinned with black hair, blue eyes and nice big c cup tits. We are both kind of nerdy and met at a comic con. We have dated for about 6 months and we’ve had an open relationship pretty much the whole time. Our sex life consists of oral mostly because we are limited with intercourse due to her butt. Early in our relationship we realized we were limited with intercourse due to me having a 4.5” dick and her curves. Her butt is really just too big for her favorite position, doggy style. We basically have to have sex with her legs bent up over my shoulders and it’s just not enough for her to cum without a ton of oral first.

   So we have the best relationship outside of the bedroom. We both like all of the same things and have the same sense of humor. We do everything together and don’t really hangout with other people that often outside of work. She works as a hostess at a restaurant and I work at a comic book store. We both like to smoke weed and probably drink a little too much on the weekends. We are truly in love and just found it works better if we sleep with other people from time to time. I like to sleep with petite girls and she likes guys that are atleast 7” long. 

 We had an agreement to always sleep with other people away from the apartment but after about 4 months into the relationship circumstances changed due to her hooking up with a married guy (she didn’t know at the beginning). I was at home one evening on a Saturday drinking and smoking a little. Tiff had went out with a friend from work to have some drinks at a bar a couple blocks away. She had texted to see if I was still up and at the apartment. She asked if I could maybe go for a drive or go out for a while so she could bring a guy by the house. I said I was too drunk to drive and I could just hangout on the couch. I told her to just tell him I was her roommate. 

  About 15 minutes later Tiff walked in with a man, maybe mid 30s. His name was Calvin and he was a 6’2 220 lb clean cut black man. I was kind of taken aback because I knew Tiff had never really been into black guys. Anyways, Tiff introduced me briefly as her roommate and as Calvin and Tiff went into our bedroom Calvin turned and apologized ahead of time if they were too loud (we only had beads in the doorway). I assured him it would be fine and I’d turn the tv up. Things were quiet for a few minutes except I could hear some gagging. I knew Tiff liked sucking dick and was good at it so I knew what that sound was. Then I heard them move around on the bed and then I heard it “oh fuck me that’s deep” Tiff moaned. “Damn you white girls are always so tight” Calvin said back “I’ll take it slow until you are good with it”. 

 I got up off the couch and moved closer to the bedroom to hear better. I peaked through the beads and seen Tiff bent over the bed with her pale ass in the air as Calvin was giving her long strokes. Tiff was very vocal with how good it felt. Calvin started to slowly fuck her deeper and harder until she had the biggest orgasm I’d ever seen her have. He pulled out his dick to let her come down from her orgasm and when he did I got my first glimpse of his cock. It had to be 9 or 10 inches and as thick as a coke can. Even more impressive was the head of his dick was bigger, almost as big as my fist it seemed. The base was covered in a white froth which I thought was weird because I knew he hadn’t came. They readjusted and Calvin laid down on the bed and Tiff climbed on top with her back to me so I had the perfect view of her ass. I swear I think Tiff might have got a glimpse of me at the door. 

 Tiff rode him for probably 10 minutes taking his entire length. She must have came 3 times. I’d never heard her cum so loudly even from oral. Finally I heard Calvin ask “you on the pill?” And I heard Tiff reply “uh huh” and he grabbed her big ass and started really fucking her hard before he grunted LOUDLY and smashed her ass down on his dick. I could see his balls lift and lower 7 or 8 times as I heard Katie say “Oh my fucking god!” As she ground her ass onto him. She rolled off of him and I backed away from the door before they saw me. 

  I went back to the couch and hid my hard on the best I could. A few minutes later Tiff and Calvin came out and he gave her a kiss at the door and Tiff told him to text her before he left. Tiff got a drink and came to the couch and apologized about being loud and that he didn’t have a private place to go to because family was in town. She kept apologizing but I assured her it was ok and it was just sex. Then she noticed my hardon under my sweatpants. “What’s this?” She said as she reached over and grabbed my dick. “You are harder than I’ve ever seen you” Tiff said before pulling it out. I told her I had peaked in and saw her riding Calvin and it turned me on seeing her cum so hard. tiff slowly started jerking me and biting her lip. “You like watching me ride a big dick? Oh god… he was so deep..” Tiff said as she smeared my pre cum all over as it dropped down my dick. “Damn, maybe I should ask him to come over again so you can watch me cum hard on his big black cock” Tiff teased as she jerked me faster with about 3 of her fingers. I almost passed out as I shot cum up over my shoulder and over the back of the couch. “Holy shit! What the hell was that?!” Tiff said shocked at how hard I came. “I guess I know what we are doing tomorrow night” Katie said as she laughed and got a towel.