Is it possible to do without slowing down? If anyone can consistantly get it, how do you do it?

Yes, you literally just jump...

Just because you might not be doing the perfect triple jump, doesn't mean you're actually slowing down.

Now if you're refering to W3-Ghost House, the fastest way is to have one jump off the little tiny pumpkin enemy that's walking down (only found in the area with the third coin.)

Otherwise you could try a different approach and wear a blue shell, not activate the stairs at all, and as long as you are rolling inside the blue shell, you can go up without needing those stairs.

Hope this helps <3

cros, are you talking about the end of 1-1? Because there is a consistent way to do that.

Yeah excuse my ignorance, walrus makes a good point.

I totally bypassed those end level stair cases.

1-1 has a neat trick where you can triple jump over the last red koopa, which will allow you to land on the far side of that platform, and then you could reach the flag normally from there with a full height regular jump without losing any time at all.

There are other levels too where improvising does the trick. However, some levels are unfortunately only gonna not lose time if you're good at positioning yourself.

Here's a clip of it from one of koffing's videos (at 1:00):