A teaspoon is normal. Lots of references to this in popular music, like the classic rock band named 10cc, and the Flaming Lips’ “A spoonful weighs a ton.”
Like others have said, going a long time without cumming will make you produce more, as will edging or situations that build up the sexual tension. There is a lot of fake cum in porn, lots of sleight of hand used to make it look the guy is shooting more or further than he really is. No, I don’t know all the details, but I don’t need to know how a magician does the tricks to enjoy the show either.
As for distance, I personally shoot at least a couple of inches. On the one hand, I have surprised myself and have it spurt a foot or two … but on the other hand, if it’s my second orgasm in a short time, it might just dribble out. I suspect there’s a lot of natural variation.
That said, while Erin is absolutely right that you shouldn’t be AT ALL worried about this in terms of pleasing your partner, but there is more to it, and is a good idea that you asked. I have heard of a situation, especially with aging guys, where they cum internally but nothing comes out. That CAN be an indication of a serious medical condition, from what I understand, I don’t know very much about it, but it sounds worth a Google, and then you should visit a urologist (despite the title, they don’t just deal with pee) if you think it might apply to you. Best wishes.