A question for gentlemen who have had a vasectomy?

This is a pretty innocent question about a not so innocent subject, but curiosity has gotten to me. When men have a vasectomy, what exactly happens when he achieves ? Usually he s semen and sperm, but when a man has a vasectomy, what happens? Is it just the liquid without the sperm or does he just kind of... 'fire a blank'? I'm curious.