Here's what you'll need:
-100% cotton, white, low-rise, fly-front briefs (a.k.a. "tighty whities", or "tidy whities", or some variant depending from where you hail),
-a work space to get dirty (outside if possible), and
1 Tie-Dye Kit (I ordered this one through Dharma trading company, at the recommendation of this great Instructable),
Rubber bands, soda ash, dust mask, latex gloves, several colors of dye, and squirt bottles.
A big thanks goes to my friends Bridgette and Lucy for help tie-dyeing and documenting!
Step 1: Prep your undies
Make sure to wash your undies before starting, as new store-bought fabric can get streaks when dyed. Also, if the fabric is damp but not dripping when you start, the designs will turn out crisper.
After you've twisted, tied, and banded, you'll need to soak the items in a soda ash solution before dyeing. This will help the dyes bond to the fabric and keep your undies bright and brilliant for longer. Wearing the dust mask and gloves, dissolve 8 oz. of Soda Ash into a gallon of warm water. Soak the undies for 10-15 minutes, and wring out the extra solution prior to dyeing.