ladies only ...what about the guys who happen to be interested in guys?? lol
To answer your question...it depends which one i'm with

No but seriously...it really depends on the situation, there are times where guys have cum in about 2 mins...and then i've had sessions lasting hours...average is probably about 5 mins i suppose...but foreplay would make guys cum faster and also how horny they are.
Lots of factors really.