How to Rosin Your Bow
Rub rosin on the bow, gliding it across the hair a few times, until rosin covers all of the hair. The rosin will make the bow look a little discolored when enough is on.
The bottom and top of the bow will need a bit more rosin.
The larger the instrument, the more rosin it will need. Rosin gives the bow texture so that it can grab the strings to vibrate and make pitch. The larger the string, the more grit it will need.
Tip: Rest your thumb on the bottom of the frog (the metal piece) so that you don’t accidentally scrub metal with rosin.
Rosin every time you play, or once a day should you play more than once.