You "feed" lodestones iron filings. You "feed" High John roots...especially whiskey or rum, incense, ejaculate, etc.... But I would not use the term "feed" for gris-gris. I am splitting hairs a bit... But it does not make sense to feed a gris-gris bag whiskey...not to me. It would not be wrong... I would just say, "whatever".
I know of people who can't help themselves and have to spit whiskey on everything!
You work with a gris-gris bag by adding to the bag as you see fit. You can add gemstones you like, maybe a tigers eye or quartz crystal, a special coin, a trinket, a piece of jewelry... Anything that means something to you. Add these sorts of things to the bag. Cut a picture out of a magazine of the type of home you would like to build or live in.... then put it in the bag. This is how you "work" with the bag.
It is good to expose the gris-gris bag to the light of the full moon from time to time to "charge" the bag. Let the rays of the full moon light shine on your gris-gris bag for a few minutes...that is all you need. Not every full moon is necessary... I charge my gris-gris bag three or four times a year. This, also, is how you "work" with the bag.
In our neck-of-the-woods a gris-gris bag is custom made by a person who has knowledge about the items needed to be placed in the bag for a person's particular wants and needs. I like to hear the person tell me what they want in their life and what they want out of there life. I want them to be ruthless and truthful. Often I ask questions in order understand the details so I can fine tune the ingredients that I will choose to place in their gris-gris bag.
NOTE: Be sure the master/practitioner who is making such a personalized gris-gris bag is of good reputation and integrity and of good intent.
It's okay to have a bag made for someone else that you love and care about.
Anyone can make their own gris-gris bag. Just take things that you like that represent important things that you want or need and put them in a bag. If you feel that chamomile will help you sleep, and you need help sleeping, then add some chamomile flowers to the bag. The more you know about items like herbs, stones, etc., that you are putting in the bag the better the bag will be.
You don't have to work with a gris-gris bag if it is well made...It is going to grow more powerful overtime and do it's work on it's own... but working with the bag always makes it better.
Working with the bag, adding to it, helps you learn about yourself...and improve yourself as you create a better life around yourself.
The gris-gris bag gives us the edge and helps stack things in our favor. We then only have to live up to the potential of its create. These are all good things!