Terminology - Inside and Outside Reverse Fold

Here is another technique that is often used to make the "head" or "tail" of an animal in origami.  Inside Reverse Fold is the one used in making "head" of animal, and Outside Reverse Fold as its "tail".

The Inside Reverse Fold also makes perfect petals for the flowers that we're gonna be making.

Here's the illustration of the Inside Reverse Fold:

Step 1:  Mountain fold a square paper into a triangle.  Make another mountain fold at the corner along the dashed line.

Step 2:  Fold, crease well, then unfold.

Step 3:  Pry open the paper, and push down the middle crease (arrow sign) in-between the two sides of the paper.

Step 4:  Press and flatten the paper.

Looks like a "head" of an animal, doesn't it?

Now, let's work on the Outside Reverse Fold:

Step 1:  Valley fold along the dashed line.

Step 2:  Valley fold only the top layer, crease well.

Step 3:  Flip over the paper to see the existing mountain fold.

Step 4:  Valley fold the top layer of the paper along the existing crease line.

Step 5:  Pry open the paper.  Flip the center outward.

Step 6:  Back and side view of the paper.  Close and flatten the two flaps, ensuring the corner stays outward and forms a sharp pointy corner as per existing crease line.

Step 7:  Flatten and rotated 90 degree to from a "tail" like end.