[yorkietalkjilly]

This is what I would tell anyone in your situation who has a dog over 4 - 5 months of age behaving as yours is:

When your dogs crosses a line, you need to stand up, clap your hands, fix him with your eyes(all alphas use the stare to send strong message to their pack members), say "Enough" or "No" in a firm voice, walk into him until he moves, back him off and allow him to willingly learn to submit himself - not put him in any submissive position yourself. Only by learning you are the one in charge by actively controlling his actions by turning away, softening his eyes, lying down or leaving the area will he learn who his real leader is. Don't act scary or anything with him - just begin to teach him who is in control and react the same way when he crosses the line until he learns. Before long, he will learn not to do it again as he knows the discipline session is coming and start to control his impulse to re-offend. In time a simple look with a spoken "Enough", "uh oh" or "no" is all it will take to send the same message.