Cornered.

Hi.
I dont expect anyone to believe this story but its all very true and very recent. Im talking about finding my little sister naked and humping herself on the corner of our dining room table!! I was so fucking horned up watching her cute tight bum cheeks clenching and hearing her moans. She obviously thought no one was exected home so early, she kept it going for a few minutes before resorting to fingering herself to orgasm. I cant bring myself to tell her what i observed but really cant stop thinking about it. Ive wanked myself silly thinking about it. Im hoping to catch her at it again so I can get it on camera. I put 18 as my age as thats nearest to my real age. My sister is 3yrs younger than me. Her pussy looks great and her bum is so cute and slim. I really want to aproach her with this but would prefer some evidence to confront her with. I know its wrong but she has awoken an urge in me I was unaware of before now. I really want to fuck my little sister. She obviously has urges so maybe she'll be ok with us fucking each other??