* Fafner: In some historical and fictional settings (like certain schools or stories), a younger boy might be called a "fawner" or a similar term implying subservience. However, this is not a common or polite term.
* Servant/Helper: These are general terms and might be appropriate depending on the nature of the service.
* Prefect's Assistant/Monitor's Assistant: If the service is directly for a prefect or monitor (a senior student with responsibilities), this would be the most accurate description.
* Underclassman/Lowerclassman: This refers to their general status in the school hierarchy but doesn't specify service.
To provide a more accurate answer, I need more context about the type of service and the school or setting.