Tsk tsk, naughty student U_U
You learned;
Moving on;
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Gather earth chakra throughout your body and keep it concentrated and at the same time channel earth chakra into the ground below you. Turn the ground into fine sand which allows you to submerge into it and travel through the ground, while travelling you're able to sense what is happening on the surface. Return the hole you have created when submerging back into a state which makes it seem as though nobody went underground while you're travelling. This technique can be useful is used succesfully but can also be very tricky if you use it without thinking.
Perform it and list it's advantages/disadvantages.
I gather and direct my doton chakra through my legs and channel it into the ground. This cause the ground to soften up, making it easier for me to dig into it. When i've underground, i then again channel my chakra into the surrounding earth, making the hole i've made go back into it's original state. Then, using my chakra already present in the ground, i use it to detect movement.
Advantage: It's a good jutsu to use; specially when the opponent cannot see you. You can use this jutsu to appear behind him and attack. Or even, just evade OP'ed jutsu's.
Disadvantage: Well.. let's say your foe has sharigan and is able to detect chakra.. when (s)he sees your chakra underground trying to sneak up on him/her, they'd attack you. Or they could even set a fatal trap.