I'm sure it all depends on the where and how cum gets loaded into your hole!
Big long skinny dicks that unload cum deep in me take longer to come out if its been a quick fuck, longer sessions with the same cock when he has really worked my hole to jelly, twisted it around inside seem to cum out quicker. Big thick cocks do the same, so maybe there is a relationship between the thickness, depth and amount of work done when loading your hole to the rate at which the cumload is expelled?
One big thick cocked guy that used to fuck me all afternoon, stayed hard so was constantly using his previous cumload as lube, fucked me so many times in various positions my legs went like jelly, my hole throbbed and was very moist but it never let any of his juice go?
Shorter cocks that unload just inside my hole seem to make me want to expell their cum quickly, unless i can find another bigger one to push it further in!!
One guy with around 7" cums several times, each time pulling half out as he cums- i actually feel him squirt, as well as his cock throb! Then he slides through his juice, getting deeper into me each time... cums about 5 times before his balls are empty, but none of his juice leaves my body.
I've never learnt that technique, and always end up thrusting deep when i cum, grunting and throbbing as far in as i can climb, i usually stay hard for some time afterwards so will often keep pounding, working my cumload all around the interior, sometimes I'll cum again... not sure if my load stays in guys asses or not but it's sure fun putting it there or taking it!