We build something like

http://blkhatjxlrvc5aevqzz5t6kxldayog6jlx5h7glnu44euzongl4fh5ad.onion

To connect, install an IRC client (e.g. WeeChat, Irssi, HexChat, Quassel IRC, KVIrc).
Connect to the hostname blkhatjxlrvc5aevqzz5t6kxldayog6jlx5h7glnu44euzongl4fh5ad.onion on port 6667.
Route the traffic over the Tor network using the SOCKS5 proxy settings:
Hostname/IP: 127.0.0.1 Port: 9050.