I will agree with many people in this thread by saying it's the little things mostly.

The smiles he does not think I see
How he makes me shiver by doing oh so little
How I know I am his by the way he holds me, speaks to me, touches me

But on the other hand, the wicked grin in his eye when he's in a 'hitty whacky thing' mood, gets me oh so drippy very quickly.