For the drums to play brushes rather than sticks, choose one of these Jazz styles: Ballad Even, Ballad Melodic, Ballad Swing, Ballad Double Time Feel, Gypsy Jazz, or Long Notes. Then set your tempo, since these are ballad styles and start slow.

 

There is no switch that turns brushes on for any other style, and no Pop or Latin style uses them. In the Brazilian pack, Samba Brush does.

 

For more, see Accompaniment styles on the iReal Pro website.