After looking around the Internet to find the biggest archive of gay porn games, I think I've come across the collection that beats all others out of the water. Game Porn Tube is where you'll come across a huge number of Flash-embedded gay games where you can look through the hundreds of options they've made available to users of the website. Note that Game Porn Tube is 100% free to use and the voting system means it's really easy to find out which ones are the best to enjoy.
Titles range from Boy Harem Paradise through to Shake Keric Butt. The quality of the content ranges a little depending on who created the material, but the fact that you can sort by 'top rated' means you'll likely have little trouble coming across something that's worth playing. The gay Flash game library here is something worth taking a look at, so head on over as soon as possible and get to it.