Unfortunately there is currently no target available to filter on adult content. We do frequently see users write their own 'curse word filters' to explicitly filter out any interactions containing curse words. You would do this like so:
twitter.text contains "my keyword" AND NOT twitter.text contains_any "curse word, rude phrase, unwanted content, etc, ..."
I have raised a feature request with our Product Team to implement the ability to filter on Twitter's 'possible_sensitive' field. This would allow you to filter out any interactions containing links to content which the content author deem to be 'potentially sensitive'.