The earmuffs were just a cheap, red pair sold in the Sporting Goods section of Wal-Mart. The headphones were some ancient, broken ones found around the house. The paint was just regular, enamel spray paint (glossy, not flat).
I first used electrical tape to protect the (synthetic) leather that is the cushion for your ear. I applied two coats of glossy black to the muffs, but you can use as many as you feel necessary. Remember, lighter coats are better than one thick one.
I then, using a sprayer attachment bought at Lowes, went over the muff four (4) times with a mist of water. I held the hose at a distance of approximately 16 inches. You can mist the muff until you life the droplet design. Four times over was efficient in producing good-sized drops, but it is a personal opinion, so find out what works for you!
After, I quickly sprayed white paint, from the bottom and at a low angle. This gives an effect of rising bubbles.
I let the water evaporate as much as it could until the sun set, when I was forced to use a hot lamp to vaporize the water. You can tell the water is gone when you see no more raised surfaces.
Don't worry if you don't get it right the first time; I didn't either. I had to repaint one side to match the other. (I overdid the white paint by using too high of an angle.)
When I was satisfied with the effect, I put on two (2) layers of clear coat. After it dried, I reattached the muffs to the headband and proudly displayed my creation!
These headphones work great, and would be ideal as a gift for people have a high-noise job (landscaper, for example). While I won't be giving away this pair, I will definitely be making some more with different colors and designs!