The story is completely true. My 19 year old girlfriend at the time, we’ll call her Emily (I’ll call her “E” for short), was slim, cute, nice...body and a complete sexual a****l. Unlike many females then or now if I was horny, so was she. Spending a night at my apartment experimenting was fine with her. She’s the first woman to ever give me a rim job, as an example, and she initiated it. If she had a particular kink it was sharing my cum with me. I didn’t particularly care for the taste but. She took her time, kissing me again before working her mouth across my throat and chest , teasing my nipples and getting them surprisingly hard. Her lips went lower, across my stomach, tonguing my navel and stirring the hair on my belly before getting to the Main Event. Tiffany long fingers encircled my dick, and a jolt of erotic pleasure blasted through my body like lighting at her touch. She stroked the length of my throbbing prick with one hand and fondled my sensitive balls with the other.. My sister must have heard everything and known what was going on, because she walked straight in and didn't seem shocked to see me like that. She seemed...into it. I would have freaked out otherwise. She just stood there, biting her lip, watching me stroke it. Soon I wasn't watching the porno at all. I was watching her watch me. Her hands started to drift over her body - one across her barely budding tits, and another slowly moving towards her crotch. After a moment of rubbing, she pulled her. Castigate himself later on if he could manage that. Poor schmuck, fondling her bras the way he would - while jacking off his big dumb boner. Why wasn’t she getting mad at him during that period? She appeared to behave more cheery than ever, continually working harder to uplift him; comfort him however possible. If only she knew - ‘would slap me silly’.Eventually, it would get lots worse and he would actively dream of fucking Mommy’s titties. He started roping off at night about it. Fucking his.