You have been trained to fight shoulder-to-shoulder with other soldiers as a single unit. Allies may freely Disengage from an opponent you are also Engaged with as you cover their retreat. Additionally, on your Turn you may lose Momentum in order to grant Momentum to any allies you are standing shoulder to shoulder with, so long as they also have this Talent.
You can purchase this talent a second time. When you fight alongside other Allies who have also learned Drilled, this grants you +1 SL on Psychology tests.

Core Book, Page 119