How do you grease central air fan motor bearings?

If you remove the screws that mount the wire screen to the unit housing, you can flip it over with the fan and fan motor attached to it. Pull the fuse block first, of course. On all the units I've seen there is a small hole that you insert the grease tube nozzle into. Just squeeze it in, reattach the wire screen, replace the fuse black and you're in business.