We all know that braking on bends is to be avoided, but what's the correct way to slow down quickly on long sweepers when you come around the bend and find that you need to apply serious braking, you would ask.
You're right that jumping on the brakes mid-corner isn't a good idea, but there are times when we can still get caught out, despite even the best observation skills.
Long bends are the type of corner where you have the best vision, and that makes them the ones we are likely to 'hoon' on.
The first issue is that of lean angle: you simply cannot brake hard when leant over. And the more leant over it is, the less grip you will have, so we have to reduce lean by standing the motorcycle up. But in doing this, we change the arc and you start to run wide. If you're lucky, you'll be able to get the speed down whilst your new line avoids the hazard. If not, you could end up in the hedge...or worst.
Again, it really comes down to vision, by which I mean not only looking far enough ahead so that you can react, but also using enough peripheral vision that you can see an escape route to the outside, or even to the inside.
If you aren't using any peripheral vision, you will have nowhere to go and therefore brake too hard. And normally too late, as well.