For me it's a bit strange.
If I masturbate, get HJ, very tight BJ, or missionary I am very quick... <1 min to 3min... (so sad)
If cowgirl, I am 5min to 15min
If i do doggy, I can do 5min to 2 hours.
Once in a blue moon, it's difficult for me to cum.
Would love some tips! (starting to do kegel)