This was back when my brother was 16 and I was 13. It was summer and really hot out, and my parents had just left us alone. My brother (Blake) asked if I wanted to go through the sprinkler with him. I was still pretty naive then, so I said yes without a second thought. I went into my room and put on my brand new bikini. It was blue with a seashell pattern on it. I liked it because it let a lot of my young breasts hang out (I was probably like a 32B then). I went downstairs to put sunscreen on, and I saw Blake in his swimsuit getting the sprinkler ready. I went outside, and we started running through the cold, refreshing water. This made my nipples hard. Then he stood over it and let it spray up his shorts. He told me how good it felt, as I watched his boner get longer. He then dared me to squat over the jet of water.
I decided I might as well, So I took a squat with my legs far apart. It felt really good as it hit my stuff and my inner thighs, and my pussy began to swell. Then he started sexual questions to me (Had I ever masturbated, etc.). I really had never had any sexual contact with a guy before. He dropped a bombshell and asked if I wanted to get naked with him. Our yard had a fence, so I figured I might as well. When we were naked, he started feeling up my chest. I was fully stimulated now. He then asked me to rub his dick. I had always wanted to see a guy orgasm, so I went right ahead. After a little while, he told me to lay face down on the grass, which I did. He slapped his cock against my butt cheeks, and told me to spread them. I revealed my ass hole, and he sprayed it with the sprinkler. This felt incredible, I never knew my butt was so sensitive!
Then he went for broke and told me to flip over and spread my legs. I was so excited, I almost wanted him inside me now. He started rubbing my labia and clit, and soon after, a finger went up my vagina. He went on till I had my first orgasm, with a tiny bit of white girl cum in my vagina. He then kneeled over me and started jacking off. Soon, I had my wish. He shot cum all over my chest and neck. I loved the feel of it on my skin. Every time my parents weren't home over the summer, we went out and 'played in the sprinkler.' We even did it with my best friend! I still masturbate to these memories quite often, and I hope me and my brother will get to masturbate again sometime.