Use your secret weapon -- a hair dryer!
If you find that you've made a gorgeous splat pattern that you'd
rather not lose to "bleeding," then you're going to want to hit your
paint with your hair dryer on low air with high heat. This will
force the paint to dry in the shape it's in, instead of continuing
to spread outwards.
This is key to getting some of the different splat patterns and
shapes you'll see us use later. Play around with a bunch of paint,
on a bunch of fabric until you have a few splatter shapes you love!