Just in case - I've enabled the Mature Content flag that's available in each album's settings.
This will warn a visitor to the album (regardless if its password protected or not) that there may be mature content ahead - and prompts them to confirm that they wish to continue.
With albums now having settings for Private, Password Protected, and Mature Content, I realize there are a lot of variations. Here's a run-down of how they all work.
1) Private and Password albums are not listed to the public in your portfolio.
2) Private albums are only accessible to their owner - when logged in and never to the public.
3) Password protected albums are available to the public only after they enter the correct password. You must provide the URL and the password to them.
4) Albums flagged as Mature Content included in the list of albums to the public - but are not accessible until you've confirmed you wish to view the content.
5) In your portfolio, albums flagged Mature Content will not have a cover picture shown.
If you want to test how these settings will work - log out of your session, and visit the URL's of each album. You may have to make a note ahead of time, to test any private or password protected albums, as they won't appear in the list of albums in your portfolio when you're not logged in.