When you are sexually and romantically attracted to yourself.
Person: "That dude Clinton in my biology class must be selfsexual."
Being sexually and romantically attracted to one's self. It goes beyond just looking one's self in the mirror to check if everything is in place. It goes to the level of actually turning one's self on by doing nothing more than looking at their own self!
A person who is selfsexual may be seen actually flirting with themself in mirrors or becoming aroused by watching nakkid videos of just themself.
Dude One: Check out that chick creaming over herself!
Dude Two: Sheit, all the hot chicks here are either lebsian or selfsexual. We ain't getting any play here!
Dude One: No way! Selfsexual chicks are hella easy.