You can create a direct client-to-client connection with a specific user, bypassing the IRC server, with the /dcc command to set up a one-on-one connection to chat or send files:
/dcc chat message other_user_nickname
See this example:
/dcc chat how are you? steve
You can also send files back and forth on a dcc connection. You specify the nickname and file you want to send, and the other user specifies your nickname and the file name to receive it.
/dcc send steve recipe-list.doc
/dcc get john recipe-list.doc
A DCC connection bypasses the IRC server, and is direct between you and the other user over the Internet, thereby avoiding IRC network communications lags. Therefore, a DCC connection can’t be broken if the network splits.