A Sister's Secret/Finger her pussy

You quickly rush to shut the door and walk up to your sister. You ask your sister; “let me finger you” She responds “w...wha-what you mean?” , you explain to her what she has to do or else you will tell your parents. “Okay okay ...fine” she says . Before she attempts to slide off her silky panties . You rub your finger over her crotch as she sighs’ You start to feel a bulge harden in your shorts. Your cock starts to get hard. Your sister says “h..hey can we just make it quick big brother?” You tell her to shut it and demand her to slowly take off her panties. Your 7 year old sister then drops her panties to her ankles .