Like most have said, it depend on my mood and how since the last time.

Penetration is not at the front of my sexual agenda:p:p and by the time we get to that, I’m really not watching the clock too closely. So I honestly don’t have an answer for you, but if you want to send your sister over,….. I have a stopwatch.;)

it all depends on how deprived i am. due to my current situation my gf and i have a hard time seeing each other so if it's been a while i cum quick the first time. but i last longer after that first one of course, so she usually likes to suck me first. but if we've had sex in the last few nights...well let's just say ' i can last all night' has a meaning to me. i've made her nearly pass out in pleasure before as she's cum time after time, but i've yet to. so it all partially depends on the body i think as well as the mindset.