I also here these claims about ways to improve your cumshot and by improve it is generally distance and volume. Myself and Jazzer have are great when it comes to cumming. I remember a story Jazzer told me once. He was watching porn having a wank and was focused on the chick in the video. He did this for however long it takes him and when he came to cumming things went off and he ended up hitting his chin and neck. I have similar cases of shooting up to my chest and over my shoulder so we have distance done. As for volume I can get a fair bit out but i generally average three or four streams of cum and I am sure Jazzer does his fair share.
The short answer when it comes to distance is there is not really much you can do. You can change how you wank keeping yourself hard and aroused for a long time can often lead to an explosive finish. I also hear that men with foreskins can improve their distance by making sure it is pulled all the way back before they cum, but seeming as I am cut I cannot really test that. Other then this there is not much you can do however that is not the end to your shooting dreams if you are a dribbler. When I first started cumming I would dribble but by the time I was about 14 - 15 years old my cumshots got bigger and bigger in distance and volume. This is a trend that has been observed in a number of surveys and I have a lot of friends who say the same thing. "As males mature into adulthood, their semen is ejaculated with greater force than when they were younger" - Jackinworld.
As for volume there are a number of things you can do. The first and foremost is stop wanking. If you are wanking a couple of times a day then you physically do not have the time to replace all the cum. The second thing that you can do to increase volume is to eat a healthy diet. The healthier you are the better your body works. Also if you have a good diet studies have found that you get longer and harder erections so there are a number of positives to a health lifestyle. I hope this has answered some of your questions, if you have any tips post them below and happy cumming!