When attempting a Superslide or a Megaflip, you can sometimes accidentally cause what is known as a Weirdslide.
A Weirdslide can be anything from Link glitching into the ground to Link sliding back and forth rapidly. If you extend the slide into the air you can walk sideways and you will hover in the other direction. This is an example of the superslide's negative speed.
It is worth noting that although it only lasts for about 2 seconds, a Weirdslide can give Link a high speed without being stuck in an animation like Superslides, so he can move around and use items during the slide. The speed is the same as a superslide (18).
If you alternate frame perfectly between a direction and neutral on the control stick, you can preserve speed and perform what is called an A-Slide (Analogue Slide).
This works on anything you could megaflip off of. Works with Nayru's Love, too.
If you want it to be perfect, you need to hold a direction for 1 frame then go neutral for 1 frame, direction, neutral etc... so only a TAS can do it correctly.
Weirdshots can be done with normal weirdslides or A-slides.
Experiment with many things like stick angles and how many times you tap the stick back. Try doing it sideways too.