Footjobs are fun...but Exhausting...jeez!

Well I gave sam a Footjob last night, which is something we do on some occasions. You see, he has a foot fetish, but not a major one. He mostly likes the smell of my stinky feet after a long day at work! lol, but he's not really that into anything else.
But he does like me giving him footjobs, but he know's how tired and worn-out I get when I do it, so he doesn't ask for it very often lol. I love the feeling of his cock getting hard between the soles of my feet, but I am just not built for them! It's strange becuase I am a very active person, and do a lot of sports...but Footjobs are just difficult haha :P