The lob sevice return is one of the best weapons in competitive doubles. Here's a great drill to practice it:

Two doubles teams face each other. One side serves a second serve, and the server stays put. The receiver lobs the return over the net player and comes to net. They play the point out.

This helps the serving team learn to respond to lobs, and helps the receiving team to learn to handle an aggressive opponent.The serving team develops mobility (switching to cover the lob) and communication ("Switch!"). And it helps the receiving team to become more aggressive and learn how to turn a point around. Let a side serve until a game has been won, then switch.