Yes, eggnog is served over ice. In fact, serving eggnog over ice is a great way to cool it down and make it more refreshing on a hot summer day.  Although, Some people enjoy the creamy, smooth texture of eggnog served over ice. In contrast, others prefer it warm or at room temperature.  If you are serving eggnog to a crowd, it's best to offer both options, so everyone can choose their preferred serving style. Additionally, making eggnog from scratch may need to be kept cold or served over ice to prevent spoilage.