I've never had a problem with tearing. What I do is to unwrap slowly in the exact order in which it was wrapped.
- Turn the butter to lie on its flat side, full-paper side down.
- Now there are two flaps of paper on the top. Lift them one after the other.
- The corners of the flaps have been folded onto the stick to form a shape that looks a bit like an oldfashioned postal envelope flap. Stick your finger between the two layers of paper on the flap and tug very gently. The corners will lift from the butter stick.
- The flaps with the now-opened corners meet in the middle of the short vertical sides of the sticks. Rotate each of them around the corresponding vertical edge of the butter stick to open them.
Now you have to unstick the paper from the short vertical sides of the stick. Don't go onto the stick to pull, instead take one of the free corners and pull it in a direction away from the stick. The paper will lift from the side. Now that you have a full paper edge free of the stick, you can pull on that to unstick it from the short vertical side.
The paper is now no longer folded, it just sticks to the long vertical sides. Pull each of the long edges down towards the table.
Success! You now have a stick of butter sitting on a flat, not torn piece of paper. Cut off whatever you need.
This may sound long, but I assure you, it actually happens quite quickly in practice, and works pretty well. I can't remember the last time I tore a wrapper.
To fold it back, I find it somewhat easier to not go as complicated with folding.
1. Fold the paper over the long sides.
2. Smooth the paper over the vertical edges towards the short sides. It will tend to fold along the old creases by itself, creating two flaps on the bottom and two on the top.
3. Fold the bottom flaps up and the top flaps down to smooth the whole thing.
You may get some crumpling when a large portion of the stick is missing.