pffffffbt

When I went in to get Betty from her morning nap she grinned at me and said, "pffffffbt!" (with lots of bubbles). So I said, "pffffffbt!" back to her. And then she laughed out loud and said "pffffffbt!" again. This might very well have been our first conversation.

Here she is during her afternoon nap, saying pffffffbt (figuratively) to our attempts to get her to sleep on her back.