one day we were going to visit for grandma. me(15) and my sister (17) sitting on the back seat. my sister wanted to sleep and she put her head on my leg. her head was turning around on my penis. ı was getting an erection.i was embarrassed but i like it. i couldn't look my sister. then she seats again. i'm shocked. i wasn't know what i should it. my erect dick seems on shorts. i couldn't hide it. she touched my dick for a second then she secretly and rapidly kissed me. by the way my hand on seat. her ass seated on my hand for a second. ı squeezed her ass. ı get so horny. then we smilled. she kept look my dick. after the day we sleeping same room ı started masturbate. she knew what ı did. and she asked what you doing? ı said nothing. she get some angry, and ı stopped myself. she never come me again like that. that's our secret, sister. now she 30.