Solder paste for stencil
Solder paste is designed for use with stencils. As long as you don't buy a cheap-o low quality paste, you should be fine. I heard a good description somewhere; good paste consistency should be that of smooth creamy peanut butter. For good results with a stencil, you don't want it to be too thin and watery (like when peanut butter separates), or thick and clumpy (like the bottom of the jar).

Clumpy paste will not spread properly over the stencil, and may clog and not remain on your PCB when the stencil is removed.

Thin paste will not hold its form after the stencil is removed, and may spread out, causing bridging.

Also remember; solder paste has a finite shelf-life that will be listed by the manufacturer. Typically this is 6 months to a year, if stored properly. Your results may worsen as your paste ages.