They do sell products for men, usually cream or gel that numbs the penis so the user will take more stimulation to orgasm. A good sex lube like Wet will work to reduce friction and helps a guy last longer with any numbing agent, which can make a guy last too long. Trust me, ending up feeling like you're killing yourself trying to orgasm and ultimately giving up because you're completely numbed out ain't fun.
I advise against using any non water based, non "animal safe" lube as it could cause your girl irritation at the very least, or even a severe allergic reaction! I've used J lube (veterinarian lube) for years without issues, that would be my goto recommendation
As for the question, its pretty common, moreso I think among zoosexuals, I say this due to observance and personal expierence. (Maybe its a higher sex drive or something, or maybe its just a canines pussy is so amazingly tight and hot, that and the control they have of their vaginal muscles, pure bliss!!) Most of the time Ive reached orgasm really quick, (30 seconds to under 5 minutes at the most) what can I say, dogs just bring me over the edge really quick, why? They are amazing in bed and there's several other reasons that are non sexual but make them all the more attractive, undeniable loyalty, unconditional love, overall beauty, they live for the moment and are always happy to see you, even if you've only been gone a couple minutes, the list could go on for ages
but I'm not trying to hog your thread though.
Anyway I have found that jerking off before hand does help with endurance, there is always the possibility that you could just continue on to more than one orgasm, if you are cumming that quick, then you must be really turned on so it shouldn't be to hard to go a few extra rounds to please her as well!