first make him fall asleep then click on him
You have to play the pie tune that the Pipe Lady gave you in the Grove of Temples, Music Temple.
Go to the Temple of Hades and place the pomegranate on the 'offering shrine'. Then you'll find yourself next to the River Styx where you can proceed on your way to Cerebus to get Cerebus' whisker.
After you get the rest of the items on the list Zeus gave you,go back to the tree of immortality. (i'm pretty sure,or the computer will take you there automatically) you will see Athena..,and you will find the rest out (:
you play to it on a lute with a song from the temple.
How to get cerberouses whisker is play him the song the muse tought you. (Find the muse where you got the reed pipe from Apollo). ;)
You blow tune on reed pipe
You play him the song you learned earlier on the reed pipe.
you go the the dog and click on it so you can get its whisker
You have to memorize the music notes that Apollo gave you. Then you have to play them on the flute. (If not then I don't remember. I did this a long time ago!)
speak to the inspiring statue with the flute. She will give you a tune to play to the dog.
you play it a song fom the music temple on a reed pipe
You use the reed pipe and these are the the notes you play: blue, green, yellow, blue, red, green. And then he will fall alsleep and then click on his mouth and you got the whisker!