as it was said it really depends on the occasions. Sometimes i come relativelly fast ( less than 10 minutes) , and sometimes i last more than i want to (more than 25 minutes)( this means i get so exhausted i cannot do anything else after that...i m not an athlete you know). 90+% of the times i finish last which is satisfying i think but to achieve this sometimes i have to put something non-sexy in my mind ( soccer championship , madeleine allbright , sing the national anther in my brain ), this makes me last longer