Can Clitoris have erections?

In short, yes. The clitoris is not just what is externally visible, but extends back into the body. When aroused, blood rushes to the tissue that makes up the clit (which is developed from the same tissue that develops into a penis), causing it to become swelled with blood. This is the process of a clitoral erection. The clit is extra sensitive and has high pleasure potential in this state.