A small piping cone is useful when a full-sized bag feels clumsy: a short chocolate line, a few icing dots or a modest amount of decoration. Its success begins with the point and seam, before anything goes inside.
Use food-safe baking parchment and a clean, dry surface. Cut a triangle with straight edges. A ragged edge is harder to roll neatly and can leave the seam fighting your grip. Practise with an empty cone first rather than discovering the folding sequence over a finished cake.
Build a closed point
Bring one corner around to form a cone, then wrap the other corner around it. Adjust the overlapping edges until the tip closes and the upper rim is reasonably even. Hold the point gently; crushing it into a hard fold makes a clean opening more difficult later.
Fold the loose upper ends inward to help lock the shape. The seam should stay closed without your fingers pinching it continuously. If the cone unwinds when set down, refold it before filling. More filling will add pressure, not stability.
Spoon in a small quantity of suitable icing or cooled, workable chocolate. Leave enough empty paper above it to fold the top down. An overfilled cone gives you nowhere to place your hand and makes leaks more likely.
Make the first cut smaller than you think
Snip a tiny opening at the point and test a line on spare parchment. You can enlarge the hole, but you cannot put the paper back. Let the mixture’s consistency and the desired mark guide the adjustment.
Apply pressure from the folded top while guiding the tip lightly. If the seam opens or the paper softens, stop and transfer the filling to a fresh cone. For an important decoration, prepare a spare before starting: the useful result is a controlled line, not proving that one paper cone can survive every task.