If a client fails the DC, that means their Courtesan believes they have a STD (sexually transmitted disease). After failing a DC, another experienced Courtesan may perform another verifying DC to make as certain as possible the client does in fact have a STD. If both Courtesans believe the client has a STD, they may not have a sex party, and are advised to seek a medical doctor for further evaluation and treatment.
I personally just look for bumps, cuts, discharge, or anything that’s not supposed to be there. If you don’t see anything even a little out of norm than you should be good. Sometimes it is possible if the dc does not go ok you can have a no sexual contact party whether its just a massage, strip tease, watch the lady masturbate, or my favorite a 2 girl show!
You can failed a DC and not have and STD. Have you heard of “Pearly penile papules”? They look like bumps that are not supposed to be there. I failed a DC because of this reason and I didn’t get to party at Sheri’s. You can’t blame the girls for not knowing what they are looking at. They have to play safe and they do the best they can.