Article in English: Choose one or more marker colors to use with your stencil. Black is a classic option, and may be the most likely to help your tattoo pass as a real one. Using another color can be just as fun.  Permanent markers contain chemicals that aren't meant to be used on skin. Look for markers that are labeled as safe for this type of use.  If you'd rather not use permanent markers, washable markers are also fine. The tattoo just won't last quite as long. Another good ink choice is stamping ink, which comes on wet stamping pads. To use this type of ink for your tattoo, press a cotton ball onto the ink pad and use it to wipe the ink over the stencil and onto your skin.

Summary in Vietnamese:
Mua bút lông dầu, Sharpie là loại khá phổ biến, để dùng với khuôn tô.