I dont see too much cum as a problem though it can get messy. I tend to shoot a pretty big load typically and if it is not into a mouth or a pussy it goes all over the place. I remember once in my g/f's car she jacked me off and cum was literally dripping down the dashboard. She freaked out sceaming there is cum everywhere I look.

Just relax, go with the flow and enjoy it1!! The amount of cum ejaculated will diminish as you get older.

Maybe you can catch it in a cup and she can drink it at a comfortable speed, instead of choking on it.

Amount varies depending on many things. That's the way it works. To minimize, shoot often and don't wait too long (remaining aroused) to do so each time. But, it's easier if she just starts swallowing--you can warn her when if she cannot tell--and she doesn't stop until you are done!

Since when is shooting a large load of jizz a problem? This is a valuable asset and you should be making porn. Surely you've seen porn movies in which the guy shoots a huge load and sperm is everywhere. As luvmyclit has advised, if you shoot more than a mouthful she should just let the excess dribble down her chin. Then you can lick it off of her. When a couple uses their tongues to clean up the jizz after sex is a lot of fun. Try it.

As for those times when not much comes out, I gotta ask if they were, say, the fifth or sixth time you've climaxed in an evening. After you've shot a few loads you've got to expect that you will begin to run dry.