What should we tell her?

my little sister is 7yrs old and is very smart, she can look at me for 10 seconds and tell something is wrong or when im up to no good and im 21yrs old. she came to visit last weekend to stay and when she come over she likes to snoop through my drawers and closet, so one day she came over and she open my night stand by the bed and found my whip, oil, condoms, and leather paddle and my girlfriend was sitting on the bed not payin attention to what my little sister was doing and she had this look on her face(my little sister) what should me and my girlfriend tell her now that she is here now? HURRY PLEASE