To flag a track as explicit you do this on the track level and the option is available under the Mix details page. To access the Mix Details page go to:
1. Release Management > Release List
2. Select your release
3. Click 'Update & Upload Files'
You will then have the option to tick Explicit Lyrics.
Terms such as explicit, clean, dirty, censored etc. should not be used in the mix names to define the lyrical content.
All tracks that need to be marked as explicit should be done so with the tick box as explained above. Even if the release contains both explicit versions and clean versions.