How do black mystery snails breed ?

i know they change genders and that but what do they have to doHow do black mystery snails breed ?
Mystery snails are actually one of the few snails that have set genders.

And one of the few that you need 2 snails to breed. These snails will not overpopulate there tank unless you lower the water level and have a male and female snail.

They lay there eggs out of the water, and males mate with the females. They breathe air, so the eggs must be out of the water for the babies to live.