Adult is one of the most popular targets for spam submissions. DMOZ has zero tolerance for spam. Repeated submissions of sites that don't fit our guidelines should be deleted in bulk. If you look at a submission and see it already listed in Test: See Editor Notes Adult (requires a DMOZ editor account), see what the notes say, and if deletion is suggested, then delete the site. If it is not listed there, send it over and it will be added.
Some webmasters spam without realizing what they are doing. Some people submit over and over again in the (possibly vain) hope of being listed. This is unacceptable in DMOZ. If this is the first time you notice a particular site being submitted multiple times, You can email the submitter and explain the general DMOZ policy on spam, leaving the site in Unreviewed. If spamming continues or the email bounces, treat it as spam. But there have been a few cases where the spamming was an honest mistake and ceased.