Protect your work area with a plastic dropcloth. Wear gloves because wood stain can also stain your hands.
Sand the tulip poplar until it's very smooth. Remove all sanding dust with a tack cloth. Place the wood on the plastic dropcloth.
Shake the can of stain to mix it well, then remove the lid and stir with a paint stick.
Dip a new foam craft brush into the stain and paint long strokes onto the tulip poplar. Apply the stain in the direction of the wood grain. Dip the brush in the stain as often as desired to evenly coat the tulip poplar piece. The stain should saturate the wood and puddle on the surface as much as possible.
Let the stain sit on the poplar for five to 15 minutes. The more time you allow, the darker the resulting color will be.
Wipe the stain off the tulip poplar with a clean rag, working in the direction of the wood grain. Remove all excess stain, using clean rags and turning them frequently. Allow four to six hours for the tulip poplar to dry. If you want a darker stain, repeat the process to apply a second or even third coat. Let the wood dry for at least eight hours after the last coat of stain.