What does it mean for boys to call girls smelly sisters?

The name "smelly sister" may be an intimate or teasing name, which is generally used between the close opposite sex. The title may be humorous or playful, but it is not necessarily malicious.

The specific meaning of this title may vary from person to person or from situation to situation. In some cases, this may be just a relaxed and informal name; In other cases, there may be some teasing or banter.