from The Century Dictionary.
- noun An iron shaped like a poker, used to heat flip by plunging it while red-hot into the liquor.
Sorry, no etymologies found.
It was made of home-brewed beer, sweetened with sugar, molasses, or dried pumpkin, and flavored with a liberal dash of rum, then stirred in a great mug or pitcher with a red-hot loggerhead or hottle or flip-dog, which made the liquor foam and gave it a burnt bitter flavor.
Turn the ladies in, warm your nose with Porter's flip-dog, and come.