Cling On and Drama Boy

I took my boys to a Christmas party last night which I was supposed to be helping with.  As if the boys would let me!  Calvin did his usual dramatic throw myself on the ground entrance and the Hulk wouldn't leave my side.  He liked hiding under my sweater from behind.  Fortunately 2 boys Calvin's age showed up and saved me and eventually the Hulk adjusted.  And no one was hurt.  I can understand the Hulk's clinginess given his age (4) but why does Calvin do the dramatic entrance thing whenever we enter into a big group?  Does he get overwhelmed? Does he need that much attention?  Is he just being silly?  Must look into it.  It's getting annoying.