The S curve makes its way into many concepts beyond its origins in math to biological systems to innovation to change.  Time we apply it to writing.

Riding the S Curve! 
(car pic by jeroenbeel via sxc.hu)
The writer's S starts where all good things do - with an idea!  Hooray!  A lovely ball of an idea!  But then you have to do the work.  This is the lower curve of the S, writing, editing, plotting (that's how the pantsers do it at least.)   Heading up the side of the S obstacles are encountered and overcome, probably including a scathing critique that almost makes you throw it away and a glowing critique that makes you fall in love all over again. 

At the top of the curve you are full of the adrenaline associated with knowing it's ready.   Print.  Stuff.  Lick.  Stamp.   Mailbox.

After the manuscript is safely in the hands of your trusty mail carrier (Is he really that trustworthy?  I certainly wouldn't let him burp my baby, why would I hand him my manuscript?  And did I see the address label start to peel off as he put it in his bag? ) and after you are done hyperventilating, then the wait begins.    

You can just relax now, sip some herbal tea, attack the mountain of laundry which has grown over the last few weeks of final edits.  Just wait.  And wait.

But it's even better to hop on another S.  Otherwise, your writing skills and energy start to fade, slipping down the top of the S.  If you wait, you'll be starting again from a lower point than you are right now. 

Even better- layer those S's, so you are writing one while the other is in critique land - growing faster than would otherwise be possible.   Besides, it doesn't hurt anyone to turn their undies inside out for a day or two, so Mommy can write!

I'm currently slogging along at the bottom of the S on a MG story (which really makes me susceptible to procrastination.)  Where are you in the curve?