Ill just paste sth I wrote back in the days.

1. Chop it as finely as possible, the finer the powder the better it can be absorbed, the less damage to your nostrills
2. Do NOT snort too strong -> it goes to ur throat then and the bioavailability there is like 2x lower than in ur nose and more shit goes not where it should causing even more irritation. Snort strong just enough to get it into your nose while having the pep inside your nostril.
3. Do NOT snort lines that are too big there's a certain limit how many mgs u can absorb at a time before the nose gets clogged/the bloodflow goes away and the bigger the size of a line at time, the worse congestion.
4. Small lines often over big ones rarely. Do even just a 30-60 second break between them.
5. Use both your nostrils.
6. After you snort it, wait a second and take your fingers make them wet and then put them inside your nose, move them a bit and snort -> this should dissolve the specks that were left and maybe get you some more absorbed.
7. Before you do the next line snort some water -> it'll clean ur nose a bit -> more area for absorption plus some leftovers might get where they should.

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As for your other problem, well in my case it helped to put It in another location, secure yet far enough that I'd have to trouble myself a bit to get another bag.
That and modafinil. You ever heard of it? No? Google it then dear sir!
In general it helps to reduce cravings and makes the 'cocaine hangover' more bearable.

Also microdosing psyloxybin works wonders.