Good points from everyone.
I agree with Mike that "trapping" is a range. However from my training I have found that trapping has to be trained much more alive than many people tend to do.
Too many people spend their time doing hubud drills, chi sao, and even "simulated" headbutt, knee, and elbow drills.
In order to be good at the "trapping" (or clinching) range, you've got to spar there with 100% resistence. It's the same for grappling, and the same for striking.
I hear way too much talk about "I'll beat them in trapping range!" from people who don't realistically spar there. Imagine an opponent who is bigger and stronger then you. His neck is thick, if you get close to him, he'll lock you up, body slam you, throw hard shots from all angles if you attempt to clinch him... and if you do clinch him he'll whizzer you down to the floor before you can even establish a base. He's great in the grappling range, and the punching range...... now try to "straight blast him and grab his neck" and see what happens. See how easy it is....
Trapping range has to be sparred realistically in order for it to be effective for you. At least if you want to establish the range with a formidable opponent.
The straightblast, for example, needs to be backed up with a lot of power, speed, and strength to get someone backpeddling. If you don't develop that tool power-wise, strength-wise, etc. chances are it will NOT do much except piss off a strong opponent.
(I prefer a boxing type blast to the traditional way due to the power you get from it.)
For the most part... getting close to a wild adversary is a hair-raising experience. People will launch blows at you, tackle you, uppercut you, push you away into punches, slam you into walls, etc. You've got to be able to handle that kind of aggression.
It is NOT easy to get into trapping range with someone (if they're good) unless you train trapping range just as realistically as people train grappling and kickboxing. It has to be with uncooperative opponents, and it has to be in full out sparring a lot of the times.
My 2 cents.
Ryu