Also, you'd be better off using the 3M pinstripe tape that is sold at Automotive Paint Supply stores. (Stores that sell PPG Paints for example. You normally won't find this tape in your neighborhood auto parts store) In particular, the plastic blue variety seals a little easier and tighter then the tan fiber tape. I use to use masking tape until I discovered how much more efficient this 3M tape works.

Then as Jim recommended, you spray this tape joint with the base color to seal the joints just for insurance. If you use the 3M tape, you are doing this step more so to seal the paterns that curve and make tight turns. If you are running straight lines and patterns with 3M tape, and your surface is smooth, you really shouldn't have to worry about bleeding though. I use an airbrush with the base paint to do that step.