Nathan has a lot of cute quirks. One thing he just started doing himself is to say "uh!" and give a little bounce. He does it randomly and I find it so endearing.
Like I mentioned earlier, Nathan does a great job actually drinking from a cup. However, once he has the water in his mouth, he just opens it and lets it pour out. It is hilarious (probably why he does it -- we can't not laugh), but also really messy. We have to change his bibs and clothes constantly because of it!