Can a man ejaculate one after another? how long can it take to be able to ejaculate again once it was done already?

Refractory period: Multiple ejaculations depend on each persons individual refractory time. Age, medications, and health issues can affect this.

Rare: rare, not scientifically documented reports of repeated male ejaculation. Most men require some time to achieve rigidity and orgasm again. For young man this is a shorter period of time usually. Becomes longer as you get older. How much time varies. A urologist or sexual disorders position might be able to give you specific time periods. Sorry this wasn't more helpful. Best of luck