This is pretty straightforward. Just make sure you have four lines on a card BEFORE you press bingo.
What I did, is after the 30 bingos were called in game, I paid for an extra five balls. After the fifth ball, you have about 10 seconds to call bingo. I called bingo and it popped because I had four lines. Lines can be vertical, horizontal or diagonal.
So you don't have to rely on getting this during the 30 bingos, you can pay for an extra five balls and then call it on your own.