Oh sweet summer child.
The femboy community is a community of crossdressers (people who wear clothing typically worn by the other sex), that are typically young males. More or less, it's a way of more feminine gender expression. Many femboys are gay, but not all, similarly to them being furries. Boykisser doesn't have a confirmed name, gender identity, sex, gender expression, or even sexuality. In fact, the original creator, Mauzymice, just called it "Silly cat".
The femboy pride flag is shown above.