(1) The poet wishes that the snake should slip away without being hurt because he is harmless even to the children, so he should not be hit and hurt.
(2) The snake was lying on the sand -perhaps basking in the sun, but now when someone chases him with a stick, out of fear it slides away.
(3) To many animals God has given colour protection. The natural colouring or markings of some animals, resemble their surroundings and thus conceal them from predators. Here the snake is ‘green’ and it disappears into ‘green’ reeds, it becomes almost impossible to locate it and hurt it.