This mean a few different things. First, I'm not locked in my office all day ignoring my children and doing something fun. I am working. Writing is not always fun, definitely not relaxing and comforting. It's a demanding job, even though it's one I love. My characters are nearly as loud as my children on most days if I don't give them attention. I have to give time to my work, as much as I give time to my children.
That said, I need to put aside my work, leave my office and shut down to be with my family. Sometimes this is difficult (remember those screaming characters!?) but if I set aside time for my children and give them my undivided attention, it makes accepting my time focused on work easier for them to accept. Sharing me with my job may just be easier to accept than sharing me with my hobby.
You know that old saying "if momma ain't happy, ain't nobody happy"? Well, there's some truth to it. Our attitude and stress level affect our families. Writing -my job- can be stressful. Since my children inherently believe that writing is my hobby, they don't understand it can be stressful. I mean, hobbies aren't stressful, are they? Meeting deadlines, keeping up daily word counts, juggling a draft manuscript at the same time as copy edits for another book all while doing the primary work on the book's marketing. Those are the parts of my job beyond their understanding.
Here's what they can understand... when we make a special purchase paid for through my book sales, I mention this treat is courtesy of mommy's job. Then for a few days, they don't have to be reminded that writing is not my hobby.