Clitoris expands its size because it fills with blood as a reaction to the situation that generates excitement. So if you have noticed that your clitoris becomes swollen when you get excited or immediately after masturbation or sexual contact, know that this is completely normal and not a situation to concern. Some types of vaginal infections may also cause clitoral swelling. In these cases itching in this area and in the vagina and sometimes a burning feeling are signs of a fungal or bacterial infection. The best practice is to visit your gynecologist for a check up and to receive prompt treatment if any infection is there. Take care.