Decorate fully-dipped cookies. Use candy-dipping set to dip cookie completely into melted eggnog candy. Remove and tap off excess. Place on parchment-lined cookie sheet. Chill until firm.
For poinsettias, melt red and dark green candy following package directions. Use red melted candy in cut parchment bag to pipe petals. Use melted green candy in cut parchment bag to pipe leaves. While candy is still wet, use brush to add veins and embroidery techniques to petals and leaves. Attach sugar pearls to center of poinsettia with remaining melted red candy. Chill until firm.
For holly cookies, attach leaves and berries from holly mix sprinkles to cookies with dots of melted eggnog candy.