Snail Mating?

[Gildurath]

So tonight I was sitting by my aquarium, and I noticed my two really large snails, which were about 3" apart, start puffing this white stuff out into the water.

What was this?

Were they trying to mate? I turned the water flow off for a bit so I could watch. They seemed to be puffing the milky substance at each other.

Thanks for any suggestions to what this was.

 

[Longinus]

sounds like snail mating to me, no first hand experience with it, but that sounds like most snail matings I have read about.