Pitching the Baby
For writers, the opportunity to pitch their novel induces a certain amount of trepidation. Sending one’s baby, the result of months (or years, unlike a human baby), to an agent, brings the fear that the agent will not love the baby as much as its parent does.
So the opportunity for a pitching activity over Twitter is a blessing. It’s like one of those photo contest people enter their baby’s picture into, hoping for votes. With a Twitter pitch session, the worst that can happen is that no agent asks for a partial or full manuscript, just as if nobody voted for the baby picture. It doesn’t feel as much like a rejection.
To writers, “pit” means a pitching opportunity

I am taking part in a pitching opportunity, #sffPIT. This is a pitching opportunity for unpublished manuscripts in science fiction and fantasy, which is where I do most of my writing. I have three novels that fit this category (actually four or five, but one is not a standalone in a series, and another is a fragment which may never get finished).
To take part in a pitching opportunity, I must write twitter-sized blurbs for each of my novels and post them at intervals during the day of pitching. I have done this, setting them up using TweetDeck, so that they pop up at various times.
Now what?
All I have to do now is hope.