So my husband and I went to the Bahamas with our families. This included his parents and brother and his g/f, my parents and my sister and her husband. So we were down there from a Saturday to the follow Sunday. We first few days were fun and family packed. Getting to know the resort. Then we all started to venture on our own. It was mostly my sister my husband and her husband all hanging out. The girls would do a spa day, the guys did a jet ski and snorkel day. So that evening we were all suppose to have dinner but my sister and her husband didn't show, no big deal figured they were tired or wanted to do there own thing. The next morning I asked her what happen she said they wanted to be alone and went for a long beach walk. Funny because later my husband said that Matt (her husband said they fell asleep early. Didn't think much of it. Then again that night they didn't show for dinner....So this time after dinner we decided to find out what was going on. Everyone else retired to their own thing, but we want to catch them red handed...we figured they were playing hooky or something...We walked over to where their bungalow was...it has a beach access patio....I decided to take a peak figured they weren't there anyways. But as I got close to the sliding glass door I heard moaning and thought that's why they skipped out, they were to busy do the nasty. My sister and I are close and have shared detail over are years thru typical girl talk. So taking a peak didn't bother me...the curtain was closed but not fully, there was a crack at the end. I looked thru there and that's when I was frozen in my tracks. There she was bent over the bed getting drove hard by a black guy that was at least 6'8 and had the biggest dick I have ever seen. Matt was sitting on the bed as she sucked him watching and smiling as this guy fucked my sister. His dick was huge...I would say a ruler long. Now her husband was big too at least 8 maybe 9. I stood there and watched for what seemed like a hour. Then my husband was like what's taking so long. I hurried and said nothing they were sleeping and we left. Now that image was in my head all night now. The next morning I saw them at breakfast and said so y'all have a nice night again. She said yea we feel asleep, this time difference is killing us. I looked at her and said yea but I be you are still enjoying yourself. Now this night after everyone excused them selfs I told my husband I would be back as I was going to go talk to my sister about plans tomorrow. He said ok he'd be here. So i did the same thing snuck up to there patio...but I didn't see anything this time. As I was about to leave I caught something in the bathroom. I could see 100% of everything because of angles, but in the mirror I could see the top of her head bobbing back and forth and see that black guy in the mirror. I watched and thought were is Matt. About a minute later he came thru the front door with some a bottle of wine, and said oh I see started without me...and they all made their way into the living room. Matt started to strip as my sister and the black guy came out of the bathroom. I watched that huge dick bounce from side to side as it stuck straight out. My sister went over to the couch and sat down and lend back, spreading her legs. I figured Matt would go over to her, but he just stood there stroke his dick to live, as that guy walked up to her and sank that huge dick straight into her, I mean all the way. She let out a sigh and Matt said see babe I told you that you would enjoy this and with that, she said back...Yes I should have never doubted you and I hope this can be a on going thing. Matt stated that they will find a big dick for her when we get back to the states. Anyways, that guy pounded her hard, I thought he rip her in half. They did it every which way...My sister must have came 30 times it seemed. Then finally he said you ready, but he was looking back at Matt. He got up off the chair walked over to the bed where they were now and stood close by. Then with about 5 more pushes that guy cummed in my sister. He pulled out afterwards and you could see his cum running out of her. Now what surprised me most was soon after that, Matt took his place and started to fuck her...cum dripping out and everything. As his dick went in and out I could see the cum on his dick. He didn't last to long before he too unloaded in her. Then what got me, was Matt then proceeded to eat her out afterwards. Licking up everything. My sister was moaning and bucking around. The black guy walked over to Matt and this is what shocked me...Matt reached up and sucked on his black cock. he went back and forth between my sister's pussy and his cock. Then the guy was hard again, Matt took him by the dick and placed it back in to my sister and they went back at it. I heard my sister tell Matt, that tomorrow she wanted more black dick to please her. He said we can arrange that. I watched till he came again and Matt sucked him and her clean and then I went back to my room...I walked straight in and stripped and fucked my husband like nothing before. He said what has gotten into you...all I could think about was that black cock fucking me and having him suck a dick that just filled my pussy. He said man I might have to send you over to your sister for more girl talk if this happens. If he only knew what might come of that.