I like to use handmade paper cones if I need only a small amount of a mixture such as chocolate, royal icing or buttercream for decorating. They are quick to make and have the added advantage of being disposable. You may snip the tip of the cone off with scissors, but I find I have better results if I try to roll the tip to the size opening I need. Sometimes the cut surfaces of the opening will make squiggly rather than straight, even lines when you pipe. To make a paper cone (see illustration):
From waxed or parchment paper, cut an 11-x-8-x-8-inch triangle (or fold a square of paper into a triangle). Hold the triangle in one hand with the longest side at the bottom and the thumb of your other hand in the center.
Bring the lower left-hand corner B up to corner A and hold together to begin to form a cone.
Wrap corner C around the front of the cone until it meets point AB.
Fold ABC into the cone until the fold is level with the front to hold the paper cone together. To reinforce the corners and seam, you can tear a small tab on either side of the back middle seam. Fold this tab into the cone.
Fill the paper cone half full; fold the two sides toward the middle; fold the top down to enclose the mixture. Cut the tip if necessary before piping.