When it comes to pruning a Christmas cactus, it's important to know the proper technique and timing. In general, you should prune your Christmas cactus in the spring, when it has finished blooming. It's best to wait until the blooms have faded and the plant is beginning to grow new leaves. Pruning should be done carefully, using sharp and clean pruning shears or scissors, cutting just above the node (where the leaf joins the stem). This will ensure that you don't damage the stem or cause unnecessary stress to the plant.