1. behave extravagantly (usually refers to spending habits)
push the boat out and buy new clothes/car
'To push the boat out' means to spend a lot of money on something, usually in order to celebrate. "When I make a really good sale in work, I like to push the boat out and celebrate by going out to dinner with my husband." "I don't see my friends very often so when we do meet up we like to push the boat out and go somewhere nice for cocktails." This is an idiomatic expression similar in meaning to 'I like to treat myself', 'extravagant', 'splash out' and 'splurge'.