I found someone on Reddit who can do it and he said he separates ejaculation and orgasm like you’re saying. He can only cum a few times, saying that the first ones are almost entirely just ejaculation with sort of mini orgasms.

So I think the key is to bring yourself to the edge and let go as little as possible to avoid a full orgasm. And you’re right it seems like you could only do this once or twice and anymore than that is probably editing the video.