Blocking adult websites (with exceptions)

On Mac

• Open or create a block and choose Pre-made lists → Adult. It adds about 180 adult sites in one go.
• To allow a site, remove it from that block's website list. Exceptions are simply sites you leave out.
• To close the usual workarounds, also add the Proxies / VPN list, and the Google Images list if image search is a problem for you. Avoid the Search Engines list for this: it blocks google.com, which takes Gmail, Google Docs and Drive with it.
• Add a lock (and someone else to hold the password; see Let someone else hold the key) so the block can't be switched off on impulse.

Related: Can FocusDragon be bypassed? · Let someone else hold the key.