Howdy John, guys can hold back ejaculating. Thats what I usually do. It takes some time and practice before you can fully control how you orgasm and ejaculate, maybe months. I prefer to hold it in, especially if I'm not in the washroom, so I don't wet myself. Also, it feels different.
I'm going to tell you what a Doctor told us in a seminar for young guys that asked that same question.... holding it back or trying to hold it back for any reason on a continuous basis, is really a bad idea. The purpose of ejaculating is natures way to clean out your glands. If you ever noticed, he continued, semen contains tiny little globs. If these little globs are held back,they tend to accumulate. If this happens, over time, you got a good chance of clogging up your glands.. then when you finally try to ejaculate, the amount is way down or you can't. He said, believe me, you don't want that...you will be incredibly miserable. However, if this happens, he said very warm baths might help it out. Apparently, he was a Medic in the Army and some guys had this very problem.
That's why in previous posts, I suggested letting it all fly out and to do it behind locked doors..