Demisexual falls under the Asexual Umbrella. It means that one experiences sexual attraction only after a close connection has already been made. It is used as a label to describe ones sexual attraction level. For example one can be a Biromantic Demisexual. Here are some resources for it from AVEN which is an Asexual Awareness Group.
Speed is of the essence young one. I shall teach you. Now call me Sensei! Just playing, my leadership skills are terrible and I would no doubt lead you astray. Lol.