Snot
Boogers
noun
Maybe you didn't know this, but if you're like everyone else learning a new language, you learn the cuss words first. くそ is sh*t / garbage, though it's not really a "bad" word in Japanese like it is in English. So, what is your nose sh*t? It's your snot and boogers. Ewwww, stop eating them!
The reading is just like what you learned with the kanji. はなくそ.
かぎ鼻の男が、ほじくり出した鼻くそを、ねむっている低い鼻の男の鼻の穴に入れるのを見ました。
I saw a man with an aquiline nose pick his boogers and put them in the nostrils of a sleeping man with a short nose.
指でほじくり出した鼻くそをティッシュの上に集めています。
I'm collecting the snot I pick out with my finger on a tissue.
フグが僕のことを自分勝手だって責めるんだ。目くそ鼻くそを笑うだよね。
Fugu accused me of being selfish. Talk about an eye crust laughing at a booger.