Frog base
The frog base is a traditional starting shape made by squash folding and then petal folding all four flaps of a preliminary base, giving a slim form with many long points.
Start from a preliminary base. Lift one flap upright, open its pocket and squash it flat and symmetrical; repeat on the other three flaps. Then petal fold each of the four resulting diamonds, just as you would when making a bird base. The finished base has more points than the bird base, which is why it is used for the traditional sitting frog with four legs and for flowers such as the lily.
It is a long sequence of repeated moves, so small errors add up. Keep each squash fold exactly centered and each petal fold symmetrical, and work on a large square. Despite the name, the Jumping Frog on this site does not use a frog base; it is folded from a card with a waterbomb-style collapse.