It's not every day kids run to grab their toothbrushes. But for this delightfully drippy Valentine project, they just might.
Fold the cardboard stencil, heart side up, over the white paper card.
Lay out plenty of newspaper to protect the work surface.

Squirt some paint onto the bristles of the toothbrush, then, holding the brush over your card, rub your thumb back and forth across the bristles so paint sprays off and spatters through the heart cutout onto the card below.

Let the paint dry, then use markers to write your message.