Gj. Now moving up to C-rank.
First one is pretty much like the one you just performed, but this time you create more senbons, thus higher rank. What's nice about this one is that if you have an opponent you could actually form senbons from your gourd and from the ground at the same time. This means you could basically use the ones from your gourd as a diversion while your opponent being unknowing of the senbons behind him/her. Sorta how i use my CW sometimes and it works pretty good. You're not limited to using the gourd ofc.
Next up is our first full-fledged defensive move. You gather iron sand and form a shield to whatever shape you want and repel streams, projectiles or taijutsu moves. You could pretty much block any jutsu that is of those forms and being of the same rank, since Iron sand is neutral to all basic five elements.
Whats not very clear is that if you would face spikes from under you, you could basically form iron sand under you and neutralize them. That is if they are of the same rank or a rank under C-rank. This includes some doton moves though that it could used to counter.
Perform these two.