georigami:
Start with a frog base. Fold one flap in half.
georigami:
Like this. Repeat in all other 3 flaps.
georigami:
This is how the model should look like after you've folded each flap in half.
georigami:
Unfold one flap and reverse some creases as shown to do an open sink.
georigami:
This is how the model should look like after one sink.
georigami:
Sink away in all flaps and you'll get this. Fold the top tip to an existing crease.
georigami:
Like this.
georigami:
Put your finger inside the model and make it 3D.
georigami:
Make a closed sink at the large point. This is not easy but it doesn't have to be done very tidily.
georigami:
Turn the model over and bring down one flap.
georigami:
Bring down the next flap and place it on top of the previous one.
georigami:
Bring down the next flap and place it on top of the previous one.
georigami:
Bring down the last flap and place it on top of the previous one and beneath the first one.
georigami:
Pull opposite flaps and arrange some paper to obtain the finished model. Making the small flaps perpendicular to the model will help make it stay 3D.