Do Not Knock on Head

Guys, DO NOT go by the girl you like, or ANY girl and knock on their head like you would if you were knocking on the door. It is SUPER DUPER ANNOYING and will cause her to hate you. I know because I am a girl.
Instead' put your hand on the top of her head and keep it there for a long time. (**she may get nervous and put her hand over your hand that is on her head (' ).