If you have little to no experience riding, or still are learning to ollie, then a 360 pop shuv can absolutely be difficult. However, I rarely see a true 360 pop shuv, most ppl just shuv without the pop.
First you have to know how to do a Kickflip, and a 360 pop shuv-it. And basically you pop the board around like a 360 pop shuv-it, and flick it like a kickflip.
i hope this site helps. This is how to ollie http://gaster-skatetricks.blogspot.com/2009/10/how-to-ollie.html And this is how to pop shuv it http://gaster-skatetricks.blogspot.com/2009/10/how-to-pop-shuv-it.html Maybe you could be able to distinguish the two if you learn it properly.
ollie, pop shuv-it, kickflip
Pop Shuv it Underflip
well.. a front pop shuv with a heelflip is a varial heelflip but a back shuv with a heelflip is a inward heelflip
1. Ollie 2.shuv it 3. pop shuv it 4.180 5. kickflip 6.varial kickflip that should get you started
Pop it
its like a 360 flip but a 360 heel flip its a combination between heelflip and 360 fs pop shuv it
you have to try to jump of the skate board or if your falling off fall on your back side
Put your back foot in a pop shuv-it stance and your frontfoot in a kickflip stance. then pop you board up and scoop your back foot. then catch the board brfore iot turns twice, and land.
the reson it is turning 90 degrees is that you are not getting a proper flick after the pop or it could be that your foot is in a pop shuv it position :/ i hope that helps :)