Exactly what does it mean to "Call Lottso"? I've played the Lottso card…

Exactly what does it mean to "Call Lottso"? I've played the Lottso card, and won it, or not, but I can't figure out what conditions are necessary to "call" Lottso. Must call it 10 times in one of the parlors, so...

Winning it did not necessarily mean calling it, and not winning did not necessarily mean calling it, either.

Thanks.