I believe the smell you’re describing is his male musk due to hormones raging. We recently neutered our Duncan and he still has some reserves here and there where he will get over excited and have this musky/fresh-oniony smell to him. It’s becoming weaker, fewer, and further between now, as it takes several weeks to clear their system after neuter… but if Hercules isn’t neutered then he’s got plenty of hormones to spare.
…And chances are, if you smell it and he’s mounting your leg, he thinks YOU”RE the lady-bunny/mate.
Remember, testosterone surges are needed to be a big tough guy, and a “romancer.” Chances are some of his poops and his pee occassionally have the same or similar scent. The mounting and the musk will go away after several weeks once he gets neutered… as will some of the territory/seemingly-random rages.
I’m not sure how old Hercules is, but he’s obviously now at least a teenager and old enough to be neutered. 