You can use the bottom of a small glass or a pestle to make a firm crust. (easydessert.org)
Place a parchment square atop the crust and press the nut mixture flat using your fingers or the bottom of a small glass works great. (biomeonboardawareness.com)
Assemble the parfait by adding a couple of tablespoons chia seed jam at the bottom of a small glass. (goodeatings.com)