Well, you might be asking yourself, "Gillian how have you and Chuck written all the music for Cougars!?"  That is a great question, because it is not a simple answer.  The first time we did Cougars! as a Triple Feature at the Annoyance Theater, Chuck and I would compose together.  I would write lyrics, then we would record what I heard in my head, and then he would rough something out.  We would argue and eventually a lovely song would come out.  
This time is different.  Chuck is on "The Spirit" a Norwegian Cruise Line Vessel for Second City, which means a great majority of the time he is in the middle of the Gulf of Mexico.  It is dang hard to write together over an ocean, and you can't really sing over skype.  Although, believe me I have tried.

So first I made these ridiculous youtube videos of me singing what I heard in my head.  That is not a pretty video.  Well it turns out you can't download a youtube video very well when your in the middle of an ocean.
So I found "dirpy", www.dirpy.com.  Dirpy takes any youtube video and turns it into an MP3.  It's a pretty dang ingenious.  
So I sent those along with lyrics in an email, and Chuck would rough something out, and send it back to me.  He sings the characters name over and over in places he feels like there needs to be more lyrics, or hums along a tune.
So I listen to these snappy tunes and hammer out the changes.  We go back and forth and argue, gently :), and eventually a song comes out.
"But Gillian, how does the cast learn the music without Chuck?"  Great question.  He sends karaoke versions of each persons part and we do our best to put it together without him.  Then when he comes back in late March, we have extensive music rehearsals to fill in the gaps.  It ain't easy but pretty sure we beat the high seas.