Imagine that you have a craving for pizza. You just really, REALLY want a piece of pizza right now. Think of that as how a sexual person can crave sex or sexual contact. An asexual person never gets that craving feeling, but if they were given pizza, they'd happily eat it and enjoy it. And some people just plain don't like pizza. And some people will eat the pizza even if they're not big on it because their partner was craving pizza for dinner and they like seeing them happy.