Blangonga - how to Slay this fast?

I've slayed this monster using the Iron Hammer
but how can I deal with this monster faster?

get under his back legs with a fire GS and swing it around thats how i deal with him and bring flash bombs and thawing agent

If you had farmed the Kutku enough, you might have a few Kutku ears that allow you to make a pair of fire attribute duals, the duals are low on sharpness but will suffice for elements.
due to the apparent agility of the blangongo, I'll mostly pick fastr weapons and forfeit raw power some weapons have for faster movements. katanas fill in the lot nicely abeit lacking in the blocking catagory.
BTW, if you had the trenya boat running, you can get items you need to for making a fire katana early.

Trenya Boat? what about it?

Read the post you made on pokke farm.