I have one brother; he is three years younger than me. He and I had intercourse only once. I was not a virgin; I had sex one time with two boys my age who I seduced and several time with an older married man who seduced me. My brother was a virgin before I had sex with him. When he and I were teenagers there was no internet to satisfy his curiosity about girls. We didn't have much in the way of common interests and didn't spend much time together until he got curious about girls. He asked me a few ill formed and awkward questions. The questions themselves didn't really bother me but his timing was often not well chosen and I could tell he wanted to know things but was both afraid to ask and didn't know quite what to ask. After several weeks I just wanted him to get to the point and stop pestering me. So I decided to take the initiative and teach him. I taught him how to kiss and how to take my bra off then what to do with my breasts. From there I went on to me giving him hand jobs and showing him how to finger a girl to climax. I taught him how to dry hump a girl to climax too. His curiosity was pretty much satisfied and we got into a type of sexual relationship which was mostly dry humping until we both climaxed. We never did any kind of oral sex. I didn't want to and he never brought it up. One Saturday our mom and dad were gone for some dinner thing and he came into my room. We started kissing and making out like we usually did and ended up in my bed with me just in my panties and him in his briefs which was how we had done dry humping many times. He'd gotten self assured and confident in his role of our sexual relationship but that time instead of putting his hand down my panties or moving on top of me to dry hump, he grabbed the waistband elastic of my panties and pulled them down. I had a pretty good idea that he wanted to go all the way and honestly it thrilled me so I raised my hips and let him take them off. He them pulled his briefs off and in no time we were coupling and he was thrusting. Both of the boys I'd had intercourse with climaxed way too soon and I assumed my bother would too but he was much more like the older man than the two boys. He brought me to climax and as he approached his I was lost in the pleasures of the moment and let him ejaculate inside me. Later I told him we couldn't do that again because I couldn't risk getting pregnant. When I was in my 20s one of my friends got to talking and told me she'd had intercourse with her younger brother several times. He was over at her apartment and they had a spontaneous attraction to each other. They were both between relationships and felt a mutual need. She told me the never actually talked about what they were doing. It was more than just sexual, they dated for a couple years and then it gradually became less frequent.