Generally it's roleplays with sexual content that are marked with 18+ as it would be a major problem legally if someone was to make an effort in actively approaching a minor. Some people use it for just adult content like drugs, violence, or coarse language. 

Starting your own check is probably your best bet in a 1x1. You can list that your not 18 and don't want any of that content as well. Also give you a bit more control on the style of RP that you want too.