Now the shadows. Create a new layer below the tongue (you can name it shadow 1) and paint the black shadow around the tongue with a small brush. Apply a Gaussian Blur filter (with a rdius of about 2px) and set the layer blending mode to Soft Light.Make new layer above the tongue layer (name it shadow 2), Ctrl+click on the tongue layer and paint shadows inside the selection (just the edges). Deselect, apply Gaussian Blur, set blending mode to Soft Light.