Have a ball!

have a ball
楽しむ

We had a ball at the party last night. 
私たちは昨夜のパーティーを楽しんだ。

I had a ball. 
本当に楽しかったです、ああ楽しかった。

Have a ball!
楽しんできてね！

I feel like having a ball. Let's splurge.