Do not over mix it or it will get grainy and soon after that you'll make butter. We want it thick enough to hold its shape but not so much so it splits. If you don't have a St honore piping tip, cut a small piece of the bag at an angle to make a similar shape. Place the piping bag in the refrigerator until ready to use. Do not make more than 2 hours ahead of time. If the cake batter is a little thick, add in an extra splash of milk at the end to loosen it a little; it should resemble the consistency of cupcake batter or pound cake.