Take a brief run or jog into your setup and get ready to hop into your block. This little hop is also called 'hurdle' in gymnastics. Make sure to raise your arms in front of you.
Sideflip
Prerequisites
none
The sideflip works technically very similar to a frontflip. They block very similarly, they rely on your arms to achieve flip rotation and a tuck to flip faster.
The concept of blocking
The concept of blocking is very helpful for any kind of trick. Blocking essentially means to turn forward travelling momentum into upward momentum. You achieve this by hitting the floor at about an 45 degree angle with your feet to get as much height as possible. Backflips can be done easily from standing but frontflips and sideflips are a bit harder to do standing without a block.
Block at about an 45 degree angle all while your arms are up and ready to initiate the flip rotation. Look at a spot on the floor.
Push up all they through your toes and swing your arms around while you rise up.
Pull your knees in and grab them or grab behind your legs. As you can see the sideflip rotates on a similar axis as the Butterfly twist. You basically roll over instead of actually flipping over.
Turn your head around early to spot the floor again.
Keep spotting the floor and stay tucked.
Done!
Tips
The sideflip does not flip over your head, instead it rolls over from one side to the other. That means you can also practice it by rolling over a shoulder high block first. Then try to get faster and faster until you can try it without one.
This flip is actually not so scary as you can see the floor 80 % of the time. I'd still recommend learning the frontflip first as it teaches you how to block your momentum properly.
You can use an undertuck like shown here, where you grab the backside of your tighs. Or you can grab in front of your knees. See what works better for you.
There are also sideflip variations that actually flip over your head. In those you can actually see the floor 100 % of the time. Imagine a tucked aerial.