This is easily missable! You need to perform certain actions before being able to do this and if you go too far you wont be able to trigger it again. In short all that you need to do to get him to sing it is to show him the rusty anchor note. You get this note from the Lola’s blue jacket, that you got from the cloak room. Show Glottis this note and he will start singing the song.
To start the lead up of events you need to have gotten the VIP lounge card, but dont give the card to Glottis yet!!!.
- Go to the VIP lounge. Dont show Glottis this yet or else you wont be able to get him to sing this song.
- Speak to Max the lawyer and try to blackmail him with knowledge of the affair. This will make him storm off and leace his cigarette case behind.
- Take this case and bring it to the security guard. She will blow it up and give you the key from inside.
- Take this key to the lighthouse (near the bees) and open the door and it will trigger a cutscene.
- Take the card you found to the cloak room of your casino. You will be given a blue coat.
- Inspect the coat and you will get a note. Give this note to Glottis who should still be sitting at the piano.