Simply brush the polycrylic on your cup in nice up and down strokes. I usually remove the paper and stick my fist inside the cup so that I can rotate it around and paint the sealer on the cup all at once. After your final coat, you will let your cup dry for 24 hours before you are able to use it.
6:4314:14How To Seal Vinyl on a Mug – YouTubeYouTube
Spray-on Polycrylic is a good option to go with if you just want to apply a thin layer really quickly. It sprays out of an aerosol bottle and is quite easy to apply. This ease of use is probably its biggest benefit.