The 'Worst' Kind of Ruined Orgasm

What could I possibly mean by 'the worst' kind of ruined orgasm, do you think?

Well, if you're imagining the kind where you're given 'permission' to cum and then stimulation is withdrawn at the very last second, leaving you helplessly watching as you leak a steady pool of cum down the side of your poor, aching, desperate cock... then no, that's absolutely NOT what I'm talking about here. 

Perversely I really like that kind of ruin... partly, of course, because I love feeling helpless, submissive and deliciously frustrated and partly because it's 'intentional'; it's what Mistress wanted to happen, it was a conscious decision on her part.

The kind of ruin I'm talking about is when you're being teased end edged and even though your Mistress stops teasing you right when you warn her you're close, you can't help but feel like maybe it wasn't quite soon enough. Maybe you feel 'something' as the cum refuses to retreat back into your swollen balls like it's supposed to, but you really can't be sure. It's so vague... it's 50/50 and you just can't tell. 

And then you feel the tell-tale warm drip on your skin as your cock gradually softens and allows its load to slowly release itself. No pleasure, no frustration, no straining, no helpless submissive feelings... none of that, just a mild sense of disappointment and failure.

But there is always a risk when being edged by someone else, maybe they don't stop quite as suddenly as you hope. It could be just half a stroke, but that might be the difference between success and failure. But then if you never lose control are you just playing way too safe? Ultimately it's probably inevitable now and then (especially if like me you don't have as much feeling as you should)... but it's still something I would like to avoid. 

Perhaps when Mistress and I re-appraise our chastity contract we can include some sort of 'penalty' or 'punishment' for unauthorised ruins. At least that would give me a chance to atone for my behaviour..?