There's a lot of pressure on guys to always initiate. Sometimes, he may not know if he's being too pushy or texting too much.
Guys love to feel affection too, and if he's really into you he will be thinking about you. Sending him a quick text will brighten his day and spark a good conversation.
Some people are more affectionate than others and there's nothing wrong with that.
While he should be able to read your feelings from your actions, some guys need a more direct approach.
I didn't realize how great this one was until my girlfriend randomly did it one day. Lip biting is another attractive things girls do during a passionate kiss.