Dear Miss Snark,
After following your advice with care and diligence, I snared myself Agent Wonderful. She is out pimping my very first book to editors, sending me updates when warranted. In short: Yippee!
In the meantime, I have finished my very second book. Friends are encouraging me to send VSB off to Agent Wonderful. But Agent Wonderful has only been shopping VFB for a short while (in Publishing Time) and I know she's working hard at it, rattling editor cages all over town. I suspect she's also busy with other clients. She knows I've been working on something. She has not asked to see it. When/if should I bring VSB to the attention of Agent Wonderful?
Tell her you've got it and ask if she wants to see it.
Generally I don't want to see book two till I've sold book one. If I can't sell book one of course, I'll read book two and see if that might have better luck.
I never shop two books by one author at the same time unless they are wildly different things such as a book of sonnets and a Western set in space.