soften up
phrasal verb
softened up;
softening up;
softens up
Definition of soften up
1
: to treat (someone) very well or kindly in order to make that person more likely to help one, give one something, etc.
He tried to soften her up by buying her flowers.
2
: to weaken (an enemy) through military attacks
They used artillery to soften up the enemy's defenses before launching a full-scale attack.