"We were 5 days into our 2 week trip, and I'd made my mind up! My Brother (Max), his wife (Alicia), my girlfriend (Olivia) and I were at an all inclusive in Mexico, and I couldn't take my eyes off of her. Alicia, that is! She'd been married to my Brother for a couple of years, but they dated since high school. I'd always had the hots for her, but I respected my Brother too much. The drinking all day long helps to blur that objection pretty quick! Olivia and I weren't really getting along the best, and we thought this trip would help our relationship, but it was only too clear we'd be done by the time we got home. So, not only was I forced to see Alicia in a tiny bikini all day, I couldn't put my dick anywhere to ease the pressure! That's when I made my mind up. I hatched a stupid plan, that just might work out that would involve getting Olivia out of our room for the night. I just started an innocent fight, that sent her straight into the arms of a stranger from Portugal. She would be spending the evening in his bed. Step one, completed! Next I had to get my Brother so drunk he not only wouldn't remember anything, but he'd be passed out in bed before any of us. Lucky for me, he's a bit of a lightweight, and called it quits by 8pm. Alicia had been keeping up just fine with me, and she felt bad for my situation, but she also wanted to make the most of our time away, so we partied! We flooded in with the crowd into the dark disco-club when it opened, and the music was pumping! We took shots, and danced for hours, pressed tightly together on the packed floor. The lights would go red every few songs and they'd play something that got everyone horny, and grinding on each other! We laughed through the first couple, but as the night went on, we raced to the floor when one of those songs came on! We were having fun! My Sister-in-Law was making me so hard, and she was well aware! She took my hand and slid it up her dress, guiding my long fingers deep into her wet pussy. I tasted that forbidden sweetness and that was all I needed! I took her by the hand and we ran to my empty garden-suite! Max had no idea his wife never made it back to his room that night!"