wrap up the whale

This afternoon Greta was quietly working on a craft at the kitchen table when she comes in to tell me;

 I have made up a song and it it stuck in my head.

Me:  How does it go?

Greta:  I want to wrap up the whale, wrap up the whale, wrap up the whale, so let's wrap up the whale, wrap up the whale, wrap up the whale.....TODAY!

Me:  I like it! So how...what do you mean by... wrap up...the whale?

Greta: Like puuuull it out of the water and wrap it in tissue paper.

Me: Excellent.

A few minutes later in the kitchen we are chatting.  I pour her some water, and because the song is now stuck in my head I say;
Here is some water, drink up...and hey, wrap up the whale!

Greta:  What is that supposed to mean?

I laugh.