I was going down on my grandma today. And I thought I tasted horse semen. And then I thought. maybe that's how she died.
This is a disgusting joke.
This is just a joke about oral sex. I didn't bring this up in any other way than that.
You need to be careful about who you make sex jokes to and how graphic the joke is. Even if you got the right audience, if the joke is disgusting, the joke falls flat.