Hi,
If you want it to lay flat, it needs to spread out. I take it the floss is spreading out too much so it ends up looking like you've got these extra "streams" of floss? I've had that happen a few times. If that's it, try wetting your fingers and dampening the floss to see if that helps control it. Or, when winding it on, use a finger on your free hand as a guide to help keep the strands from separating too much.

- Jeff