When I use them in the fabric, I intentionally crinkle up the fabric before putting the cap on the roller. First of all, it helps the curler to stay put with the extra bulk in there and it also makes for a more interesting design.
The above set of pictures are all the same fabric....photo of bottom 2 not true to the colors. I used a pink fabric printed with purple paint, wrapped in corked. I thought maybe having the paint on there would create a resist....and it does if you can see that in the photo.
but also around the middle of the bobbin .....top right
The top left was folded around a PVC pipe and the right started with a colored fabric, folded and clamped, then dipped.
I know I used marbles to wrap around and think the top left is an example...I can tell as it's more of a round shape in the middle.
The left is a scarf which needs more Indigo so it will have to be re-dipped...the right is the marble wrapped. I have to say, at the dollar store, I found the tiniest rubber bands...like 500 for a dollar...and they worked perfect for this type of thing...only need one wrap...maybe 2.