What do you know about speed ejaculation? -
do you mean the speed f your ejaculate, or the speed at which you reach ejaculation? The speed of your ejaculate does not change...I think it-s dependent on the strength of the Kegel muscles pushing the semen and sperm through the urethra. The speed at which you reach ejaculation depends on how aroused you are, and how quickly you stimulate the nerve endings in your penis head.
Do you mean premature ejaculation? Not a good thing, having sex, you finish before she does could result in a lot of frustration.