My cousin becomes my horse mate for an afternoon.
A week before I left for college, my Aunt and Uncle roped me into taking my 18 year old cousin, who didn't have a driving licence, to a doctor's appointment, because their hands were tied with other errands with my two other cousins. So I took her to her doctors appointment and returned back to her house a few hours later.
My cousin thanked me for driving her and opened her passenger door. Then she stopped and looked at me slyly before closing the door again. "Have you ever...you know...done it?" she asked with her face as red as a beet. I was stunned. I told her that wasn't the sort of question cousins should be asking each other, but no, I had never had sex.
She ordered me to park the car and turn it off because she wasn't going to let me go to college as a virgin. I hesitated but then parked the car in her driveway.
I got out of the car and she grabbed me by my arm and dragged me inside her empty silent house. We went up to her room and she sat me down on her bed. My cousin then stripped down to nothing but her tights, explaining that I had to "work for her sweets." She took my pants and underwear off to reveal my rock hard penis. She proceeded to play with it, wiggle it, kiss it, and pull it back and release it like a catapult.
Then she turned around and bent over. I had to admit, for a thin girl she had a decent round butt. "Mount me like a mad horse," she demanded. I stood up, put my arms around her and humped her. My penis pressing into her hot pink tights desperately wanting to tear through the fabric while my cousin fingered herself.
She tried to fart while I humped her, as she explained that "that's what female horses do when their happy." I really started getting into it and started humping harder, my dick pushing harder and harder against her butt.
Eventually, my cousin said "fuck it" and yanked her tights down so she stood in front of me buck naked screaming "mate with me, my big bad horse!" I humped her pussy hard as she moaned and neighed like a horse. Soon afterward, I cummed on her ass and we both laid down on her bed.
A few months later we did it again in a public steam house, but that's another story for another time