I'm looking for a a sex heavy gay or bisexual gay story(male)
Use the 'Category Search' and selecting those under 'Sexual Orientations' shows almost 400 stories. Can't tell you how 'heavy' they are.
nifty
You can find one of mine there, only it's not "heavy" (it only has three sex scenes in the entire story, though each is pretty steamy, if I may say so).
I never included it here on SOL, because I know there's an actively hostile reception to those types of stories here.
In general, you'll find a LOT more hot gay stories there than you'll ever find here, though the chances of finding the excellent ones are more difficult.
I haven't read any of them, so I don't know if they are any good, but Aussie Speedo Guy has been posting lots of gay hook-up stories. I have been able to determine, just from the descriptions, that they aren't about building relationships, but if heavy casual Gay Sex is what you're looking for in your eLit at SOL, I'd definitely check his stories out. They sound a little formulaic, but I was on a real Doc Savage binge for a while as a teenager, and you can't get more formulaic than that; if the formula happens to mesh with your interests, formulaic is just fine. He's been posting here for a year or so, I think. Rather prolific in his writing.
Edit to add: He has a definite Speedo fetish, based upon his story descriptions.