Green Grass of Tunnel

Down from the ceiling leaks a great noise
 It drips on my head through a hole in the roof
 Behind these two hills here there's a pool
 And when I'm swimming in through a tunnel
 I shut my eyes inside the cupboard
 I make sounds and through the tubes I send this noise
 Behind these two hill here I fall asleep
 And when I'm floating green grass of tunnel
 It flows back down from the ceiling, leaks a great noise
 It drips on my head through a hole in the roof
 Behind these two hills here there's a pool
 And when I'm swimming in through a tunnel I shut my eyes