Used to be known as autochristosexuality. Many people in the asexual community have found, that a fair amount of individuals that do not experiencesexual attraction to people, experience arousal to sexual activities that they are not involved in.
Karl is aegosexual because even though he experiences sexual arousal from reading things in books or seeing it on tv he has no desire to actually do it.
A person who doesn't experiencesexual attraction to others. People who identify as autosexual prefer being intimate with themselves eg: masturbating instead of being intimate with a partner.