Lennie got mad after killing the puppy and threw it.
Lennie picked up the dead puppy and started petting it, and Curley's wife coming in.
Curley's wife tell's Lennie that she likes to touch soft things too, and Lennie then messes with her hair.
Curley's wife was complaining about Lennie messing with her hair, so he covered her mouth to so she can't yell and alert anyone. She Is trying to move his hand because she can't breathe, and she wants/needs to alert someone.
Lennie killed Curley's wife, and attempted to hide the body, so no one would find out he killed her.
(wanted to fill up the empty space) Lennie is hiding in the brush so no one will find him and find out that he killed the puppy and Curley's wife. While George is going to him.