Get on like a house on fire
Definition 1 of 1
Pro Tip 1/3Speed of Friendship
This phrase implies a very quick and strong development of friendship, similar to how fire spreads fast. 
They met during orientation and now they get on like a house on fire.
Pro Tip 2/3Positive Energy
The phrase carries a very positive connotation, highlighting enthusiastic and harmonious relationship. 
Laura and Sarah get on like a house on fire, always laughing and sharing stories.
Pro Tip 3/3Casual Use
Commonly used in informal conversations, not in formal or business contexts. 
At the family BBQ, the cousins got on like a house on fire.