A little help?

I have to ask those of you out there with more than one ankle-biter child a quick question.  A bleg, if you will.  First, some background.  For those of you that don't know, Mrs. Big Dubya and I are expecting, like, any freakin' day now.  Any. Freakin'. Day.  We already have one so this isn't my first time on this particular ride - I'm an expectant dad, yes, but I lost my virginity 17 months ago in a not-so gentle fashion - not even a reach-around.

My question is, if you had your children close together, did the older one have some sense that something was happening?  I mean, did they start acting a little wonky as the day got closer?  Maybe a little off?  Little Dub seems to be a tad off-kilter as we get closer to the End of Days end.  Unfortunately, it's not as if I can sit him down man-to-man and go over the whole "Mommy's carrying a little baby brother/sister in her belly so you have to be careful..." speech.  I tried practicing all the signs for that and I think I gave myself carpal tunnel syndrome -- I am so out of shape.

So, good readers of DadCentric, I turn to you for your wit, wisdom and insight into this particular matter.  Is this to be expected?  Is it only gonna get worse?  Will I be nicknaming the new baby Ike?