Depends on the situation.
I'm usually pretty sexually dominant, but when I'm in love, I can be versatile.
In most social situations, it can vary wildly. When it's a subject I have a lot of knowledge in, I can be quite aggressive, but then there are some people that I've actually rather shy and passive around for no explicable reason; a friend who's done some astrology readings says that this may be more of a "textbook Leo" trait than some people realise -- she says that while it's more typically thought-of as Leonine to be extremely assertive-aggressive, it can still be a Leo trait to be a bit more passive, etc, around quieter people -- "playing to the audience", in a way, through a more casual form of flattery.