She also had jet black long hair and a sexy voice which sometimes put me in doubt about her age. I was only 18 and lacked the courage to take things f...rward. But luckily she was one horny woman and she soon took charge. She was 28 at that time and was divorced.So this is how it all started. One day, I returned after the last day of the final exams. It was two o’clock in the noon. She opened the door three to four minutes after ringing the doorbell.She was wrapped in only a petticoat and. I tried my best not to whimper in sheer delight but it was no use. Just when I thought my subjugation was concluded, she speared my pucker hole with her middle finger and smiled into my shocked face at the invasion of privacy.She waltzed out of the office without a single word to me. I was still on top of the desk with my panties down at my ankles and trying to control my quaking knees. It certainly looked like my sister had gotten herself into an uncharacteristically submissive position. Erin is small, only five-three, and maybe one hundred and five pounds, and she has 36-D breasts, blonde hair, and firey blue eyes. When we fucked, she was physically hot, tremendously animated and vocal, and multi-orgasmic; cumming perhaps five or six times before I would have to let go at last. When she came, she exploded, literally! She'd build up to it with louder and louder gasps and moans and then let out with a loud growl and her pussy would pulse in orgasm so hard that air trapped within. Mark rolled out of the marina slowly, but opened it up as soon as he could. This boat had some balls. We tore it straight out toward the middle of the lake, and Mark maneuvered his new “toy,” getting a feel for how it handles. After a while, we were just cruising aimlessly far enough out, you couldn’t see the shore in any direction.Sandy excused herself to go grab some snacks and more beer. While she was gone, Mark started apologizing about the previous week and hoped I wasn’t offended or made.