I've always soaked my soaps first. I didn't know there were other options. However, I definitely don't let it soak while I shower. That'd be wasting. I soak it in very hot water after the shower and before the shave for maybe 30 sec. to 1 minute. That goes for my brushes too. One minute in warm water is all I've ever needed. Since I have a thick, ceramic bowl that I soak my brush in, I leave the water in the bowl for the whole shave. Anytime I need a little water or warmth, I dip the brush into the bowl and I've got warm lather again.
I don't actually soak the whole thing. I just put enough on top to form a little puddle without running over. I do this before I get in the shower.
I find this works exceptionally well with Tabac. Other triple-milled soaps, too...but Tabac seems to practically blossom when I do this. I loves me some Tabac!
