I kissed my sis accidentally and after that she got horny

So this happened few months back. We both are really close with each other , so we often kiss each other on cheeks and hug each other. That night i was going to kiss her on cheeks suddenly she moved her face a little and i accidentally kissed on her lips. Her lips were wet so my lips slipped a bit and my lips were slipped in her mouth. For few seconds i was unable to process anything, then i immediately removed my lips and said sorry to her. She said no problem, it can happen and she kissed me on cheeks and hugged me tightly (she was without bra so i can feel her hard nippes). We both sleep on same bed so in late night i get up to for washroom but i notice my sister was fingering. Firstly i ignore it but when i remembered that kiss i got horny too. I a min i removed my trousers and start shacking my dick. She was watching porn so i was peeking it from behind and seeing whole porn with her. After 2 porn she rush to washroom. When she came back i stopped my masturbation . After 1 hr i get to washroom and picked her dirty panty and masturbate on it and put it back.