My boyfriend's cat

As i woke up in the morning,
My boyfriend’s cat
Entered in the room;
She did not know me well yet.
So I kept calling at her
To come nearby
As I was laying;
Reluctant in the beginning.
Finally she gave in
And hopped in the bed;
She came nearby
And with her chin
Touched my face,
And kept on rubbing my cheek;
«This is the code of this little alien to say hi!»
I said to myself;
«Why does she do it?»
I often wonder about these things;
Later on, we went away from his house.
As he accompanied me to my work;
When we were separating,
I went nearby my lover,
And with my face
Touched his face;
All of a sudden
I was reminded of the little alien
Of the morning;
I am doing the same thing.
And yes, it is not helping me,
To understand:
Why? or How?
Silently I headed on towards my workplace;