It's as easy as HEHE HAHA! Thats all you have to say. Joy is a fruit of the spirit which means we already have it and can CHOOSE it. That's it!
Church shouldn't always be serious, laughing in our church isn't disrespectful, it's the holy ghost moving inside of us! In the world, they say "Laughter is the best medicine", well it's true in the sense that the Joy of the Lord is our strength! And it's free, nothing you have to do or say to get it. Undeserved JOY! And no one can take it from you. NO ONE!
It's biblical too, here's some verses!
"These people are not drunk, as you suppose. It’s only nine in the morning!"
But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness
Our mouths were filled with laughter, our tongues with songs of joy. Then it was said among the nations, “The LORD has done great things for them.”
Psalms 126:2 NIV