rude noise making mommy laugh

Last night, we were in the living room.  Scotland was eating and I was on the couch with Tatiana in my lap reading.  She had her "Big Red Book" and she was flipping through the pages.  She is so serious when she does that!  It is adorable!  I also love it when she plays or reads in my lap.  On the TV, a sargeant told a private to replace someone on guard duty.  He complained, "Why do I have to do it?"  She said, "Because I said so".  Scotland said the sargeant should have replied ... then he made this dismissive, slightly rude noise.  Then, Tatiana made the exact same noise!  It was so adorable and funny.  I started to laugh.  So, she did it again.  I laughed some more, and she did it again.  Repeat.  Eventually I was laughing so hard my tummy hurt.  I would just get the laughing under control, and she then she would look at me with that happy smile and make the noise.  It was wonderful.  She really enjoyed being able to make her mommy laugh.