Gray said those boundaries include things like personal space and how a person wants to be spoken too. He said his basic class teaches verbal, physical and distraction techniques.
"Knowing what to say, how to stand, how to hold yourself."
He has been running the monthly class for more than a year, but tomorrow's course is the first one under the new name.
The course is open to women and teens of all ages. Those under 18 need parents' permission.
Gray, who had a stand at Saturday's Women's Lifestyle Expo, said he donates part of each registration fee to Women's Refuge.
The next course is on tomorrow at 6pm at St Andrews Church on the corner of Bank and Hunt St. The class runs for two and a half hours and is limited to 12 places.
The class costs $50.
To register go to www.selfdefense.org.nz or find them on Facebook at Self Defense Northland.