You should be brushing your tongue, and here is why…
Your tongue houses the most bacteria in your mouth. Even though brushing your teeth or rinsing with a mouthwash will eliminate a good portion of the bacteria, whatever is found on the tongue will deposit itself once again on your teeth, hence the importance of brushing your tongue thoroughly. Brushing your tongue can also help with breath issues.
You should brush your tongue every time you brush your teeth by going back and forth and side to side with your toothbrush and then rinsing thoroughly. If brushing your tongue makes you gag, think about investing in a tongue scraper instead.