This is one of Jax's favorite ways to show affection: NOGGIN!
Inspired by Finding Nemo's turtle head butt, Jax will sometimes gently, sometimes violently, come at you with head lowered like a charging buffalo and say, "Noggin!' and then touch his forehead to yours. It's heart-warming when he does it sweetly, and headache-inducing when he does it with a bit too much enthusiasm. But when he spontaneously gives Em a noggin, of his own accord, it makes me smile like no other.
As she gets older and more interesting, he is starting to love her more and more. Today when she was crying he yelled, "Em, be happy!" and then started jumping to make her laugh. Smile-inducing :)