No, I don’t think that’s true. Is it possible to get it just right so just a tiny bit of cum comes out, sure, occasionally. But I’ve only ever done that by accident.
Ruined orgasms mostly do spurt out, especially if you keep stroking him until it all starts happening. I think the fun variation to try and achieve is stopping just before you think he’ll cum, so he has no stimulation for maybe up to ten seconds and THEN goes over without any extra touch at all. That seems to be the most frustrating and SOMETIMES it just dribbles out rather than spurts, which is hot too.
Some more posts on ruined orgasms here: