^ this didn't work very well for me. He moves so much when he's in a pitfall trap that you sometimes hit the air. And you also bounce off on his arms when he's in rage. Generally Rajang is such an unpredictable dickwad that I found it really hard to cheese him like that so I went and whipped out my trusty glaive and learned the fight and broke his horns without much of a problem. He's quite resistant to mounting but if you do get one in you can get rid of one horn quite easily. Got two hearts and that horn after only three kills.
Black Blos anybody? Can do it with two.
Yes you need to position yourself correctly, just run at it in about an 45° angle and your gonna hit, it doesn't matter if you miss a few hits (the baseball ones are the important ones).
I failed a few times and thought i'd never be able to do it but it's really easy once you figured it out.
♥♥♥
You can also get white monoblos horn by just swinging at it with a hammer and cashing the subquest (no traps required). [Edit: Thanks to Shiinas comment, might be quicker with e.g. IG and beatdown and stuff]
If you're G2 and have any insect glaive you can also get explorer (alcohol+fish if not a daily) and go to Rathalos (Sovereign of the Sky) and mine a bit, then return to the zone where you started -Rathalos should be waiting there now- and do 2 mounting attacks to break it's back and cash out via sub.
Can net ~60k and lvl10 charms.
