This isn't the one, but I have read this one too! You really are in to cockfighting! The blog I was refering to featured an unfinished story whose protagonist is a detective (I think...?) who is involved in a cock fighting tournament.
I'm sure you've come across the Heroic Homosex site, which, for me, was an introduction to the concept of cockfighting and and frot as an alternative to traditional gay sex (which, beyond porn & fight domination stories, has never been alluring to me), but, if not, check it out: it has some very early cock vs cock stories two of which helped shape my thirst.
I love the idea of straight men taking interest in cockfighting because, though it is erotic, the eroticism isn't not derived from the perceived homo-eroticism, but, at least for me, the eroticism is derived from the idea of the pride staked, animosity, hostility, and competitiveness invested into a testosterone laden contest like this.
FYI, I have been obsessed with that epic slow motion swordfight! I slow it down even more in VLZ to make the sound of the impact more devastating.