"I shudder when relating it"

This quote from Virgil is an effective expression of concern as well as fear. It conveys the speaker's extreme emotional reaction to something they will associate. The speaker is so bewildered by the memory or story that they are about to inform that they are physically drinking with concern. This quote recommends that the tale is so horrific or stressful that the speaker is practically as well frightened to inform it. It could be a story of a personal experience, a tragedy, or a scary that they have witnessed. Whatever it is, it has left a deep impression on the speaker and they are still affected by it. The quote is a reminder of the power of stories and exactly how they can evoke solid emotions in us. It also acts as a warning to the audience that the tale they will listen to might be hard to hear.