Well, this isn't really a technique as much as it is something to do. A couple of years ago, I used to just find a hot porn and go my fastest, but now that I'm goin' for length that's different. So now I find porn that offers blowjobs, handjobs, and fast fucking to see if I can match the speed without spewing. It's honestly pretty fun and totally beats (no pun intended) just jackin your brains out to anything. Plus it makes jackin' off a little more normal. I mean you'd be surprized how long or short you could go.
P.S. If you already know this than good on ya.