What amount of sperm is it normal to ejaculate after an orgasm?

there isn't really a normal amount. it depends on how turned on you are, how much water you may have drank that day. It is supposedly around a teaspoon. But sometimes you can cum less (this happens if you have cum already recently or during that day) or more.

From my experience it will be a lot lot more than a teaspoon if you haven,t done it for a few weeks..;)