I have seen a few videos showing people pinching a balloon after it has been twisted, and seemingly pulling it away. It looks almost like a magic trick. Does it rely on the balloon being inflated fully or sharp finger nails? Is there a simple way to achieve this? Many thanks

I think you need to attend a balloon day, it is just a very sharp pull, do not twist the balloon though, this will make the balloon stronger and more difficult to split into two.

It's practice, I find that pulling it really fast generates enough force to snap it, it depends where you hold the balloon too. My way is by pushing my index finger in far as my thumb and middle finger grip it and pull it, so it's almost a pop combined with a tear. Done this way your holding the ripped part in your other hand still inflated  which looks cool.

I still can't do this - I try and try! Although the information I follow is to twist first? So will try your advise Graham and try again.

I have bought a couple of little 'balloon cutters' which just hook on a belt and they are okay - not the same though!

The way I do it is after the last twist come up slightly from it say around 2" - 3" twist the balloon basically so it don't run away from me so to speak then come up another inch or so and using both hands squeeze the balloon between thumb and forefinger of each hand and pull hard but not.direct.from each other on more of an angle if you know wa I mean.

If I want to keep air in the ripped off bit I put a pinch twist where I say to twist the balloon that usually stops the whole thing deflating before I can tie the balloon off.

That pulling at a slight angle thing really works!  I've always had trouble tearing balloons (I normally use a balloon cutter).  But I just tried that method and it worked great!  Thanks, oligunner!

ahh!!! It worked! I just exclaimed very excitedly!!

I didn't twist - and used the angle pull - THANKS GUYS!!

I just did another one!! Getting a little over excited - may need to order more balloons...

No problem glad you understood what I meant find it hard to explain some times. I think by pulling on slight angle distresses the balloon more so breaks more easily.

Can't do the third one... :-( need to practise more I think.

I get a few which are tougher to brake I assume it's down to different colours as some colours are tougher than others

I have found that if I tug really quickly a few times in a row it will break. Can't ever get it to go on the first one. I might try the angle thing next time.
Thanks