Scrape vanilla seeds from pod; put seeds and pod in large glass jar. Add cherries and sugar. Mash fruit to bring out juices. Cover and chill 24 hr.
Stir in vinegar; shake to dissolve sugar. Cover and chill 1 to 3 days. Stir well. Pour into clean jar. Seal and keep chilled for up to 3 months. Discard if mold appears or musty smell detected. Enjoy mixed with sparkling or spring water, fruit juices, sparkling wine, beer, or cocktails.
Add a splash to classic cocktails, such as Old Fashioned, Tom Collins, Moscow Mule or Cosmopolitan.