Slice the jalapeño into four slices, each about 1/4 inch thick. Cut out the membranes and seeds, so you only have actual green part of the pepper remaining.
Slice the half of the Calabrian pepper into thin strips, lengthwise, until the entire half is cut into strips. They should also be about 1/4 inch thick.
Slice the garlic clove into pieces small enough to drop into the bottle.
In a glass bottle with a top that can tightly seal, drop in all pepper slices, garlic, and peppercorns. Pour vodka into the bottle through a funnel. Seal tightly, and store in a dark place for at least one week. Or at least 48 hours if you're in a rush. :)