This won't take long but I wanted to get it down while I was thinking about it.
Yesterday when I went to pick up O from daycare I happened to wearing a shirt that really emphasized my every growing belly. I guess O hadn't really noticed it before until then and this is what happened:
O walks up, notices my stomach, points and touches it - "Oh!" (her facial expression was pretty funny too, kind of a mix between surprise and confusion)
"Yep, my belly has gotten big. What is in there?"
"That's right. How many babies?"
I think in theory she understands that there are two babies in there but doesn't really get it. It's cute to hear her say that there are two babies in there though.