U-joint replacement

When I dropped my trans I noticed that there was play in the u-joints and they needed to be replaced. Got some new ones through rockauto but I have a couple of quick questions about it.

1. New ones have a grease fitting, do I need a specific grease or is multi purpose EP2 okay?

2. Read about mounting the u-joint so the fitting is "under compression", what does this mean?

Thanks in advance
Author: thethee