I'm my sister's keeper

...But in a different way. My sister hardly ever does her work without asking me to do it for her first and usually I do. Last year it was more poems or writing assignments, this year it's ideas for scripts and almost doing the whole script for her. Though that's partially my fault, I don't want her ruining my idea so i do it for her, just in case. She's always been the childish one, no matter what the situation.