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You'll want to pick a solid white top and bottoms as the base for your cow costume. For the top, a loose-fitting white t-shirt will be lightweight and comfortable. Or, you can dress warmer in a white sweatshirt. Find some white sweatpants to complete your base outfit. Feel free to use a white dress or skirt if you prefer. If your white base garments have visible logos, don't worry! Plan to cut out spots large enough to cover these up. Working on one garment at a time, smooth out the area of the garment where you plan to add one of the spots. Place the adhesive side of the spot down onto the garment, and press around the center and edges to make sure it's completely attached. Let it dry for a few moments before repositioning the garment. Refer to the directions on your spray adhesive for the necessary drying time. To avoid getting your cow costume confused with a dalmatian costume, don't add too many small spots or place the spots too close together.
Choose a white base outfit. Press the spots onto your base costume, adhesive-side down.