Greasing a roller brake in a difficult spot!
According to this answer in reply to a question about what grease to use with Shimano roller bakes, it's important to use the proper Shimano roller brake grease and to apply it into the hole properly. The Shimano grease comes in a tube with a nozzle that facilitates proper grease application.


  Very important to follow the instructions that come with the grease - main point is to insert the grease tube nozzle at least 12mm into the hole otherwise the grease will not reach the actual braking surface.


Simply pushing grease into the hole will not be effective. Some sort of extension made from rubber or flexible plastic tube would work as long as it can be inserted into the hub far enough.

I don't think you are correct in the assertion that roller brakes need to be greased often. According to the Shimano instructions grease only needs to be added when the brakes are not working well or are making noise.