Create coffee stencil with your text on it.
Use OpenSCAD 2015.03 and stencil fonts.

Use Customizer OR:

• Install stencil font, or you will be unable to use letters with isolated perimeters (O or B)
• Open coffee_stencil.scad in OpenSCAD 2015.03
• Edit Text variable
• Set desired font name as Font variable
• Adjust Spacing if needed.
• Set Height of stencil (2.2mm ought to be enough to anybody)
• Set diameter by changing Dia (typical values are 62mm for small cup, and 83mm for mug)
• Render and export
• Print with PLA (Layer height = 0.2, perimeters = 2)

Avoid exposing stencil to high temperatures (by plunging into hot coffee for example)