"I'm a painter, Millie, a serious painter"

In the mid-late 80’s a friend of mine was practicing a scene from a play for an audition, I think it was something he chose himself. The passage opens:

“I’m a painter, Millie, a serious painter”

goes on for a bit and ends with (if I remember correctly)

“I think I just bombed out with a nymph”

It became a huge joke among our group of friends and when there was a lull, someone inevitably would say “I’m a painter, Mille- a serious painter!” with different affects and everyone would crack up. Good times.

Does anyone know what larger work this passage might be from?
Thanks in advance,

BB

From Murray Schisgal’s Jimmy Shine:

“Do you ever think about dying? I know I got years to worry about that but I cant get it out of my mind. Sometimes I think if I don’t make it as a painter, I’m going to have to kill myself. You being a nymphomaniac…why? I mean, do you get any thrill or excitement from doing it; sex must be a mechanical act for you. Yeah? Then why do you do it? Stop. You could stop if you made up your mind. I’m a painter, Millie. A serious painter. And I know how to exercise self-control and self-discipline and how to say to myself, ‘no. I will not do this-and-this I will do that-and-that.’ … Millie, wait a minute! Millie, don’t make a decision youll be sorry for! Millie!! I just bombed out with a nympho!”

(Full text here.)

Thanks!!