I trailed off as my gaze had dropped further down into Mark's crotch to see that not only was his enormous cock straining the material of his jeans, but there was a small wet spot where the tip of his cock was dripping. Apparently I wasn't the only one who desperately needed something. Looking up from his crotch I saw Mark bring his hand to his face and rub it under his nose. As I watched, totally turned on, Mark sniffed and rolled his eyes back in pleasure from the scent of his big sisters pussy. Now what kind of sister would I be if I didn't help him out...