This is very much worth two hours of your time: Jeff Vanderstelt, a pastor at Soma Communities and Vice President of Acts29, explaining what it means to have “gospel fluency.”
If you want a snapshot first, listen to the first minute of this video:
Here is the teaching flesh out at a seminar for Grace Covenant Church in April 2011:
You can also listen to this in audio: part 1, part 2.
If you only have five minutes, fast-forward to around the 27:00 mark of the first longer video to see how Jeff applies the gospel to pornography.