It's interesting that the article is mostly about how to do it badly, with little about how to do it well. Two suggestions noted are to remember to show, not tell, and to focus on the emotional, not the physical. I think that the potential conflict between those two pieces of advice is part of what makes it hard to do well.
lol reading those awful sex scenes has been the highlight of my morning
Honestly, if you write a sex scene that doesn't make you need to stop and fap after, then it's not going to turn your readers on either.
Source: Have sold erotica for $750 a story more than once. And had a GREAT deal of fun writing it! :)
It's hard to judge these out of context. Not every sex description is meant to be hot.
Bukowski went into great detail about cunnilingus in The Post Office and I am very grateful he did. I learned quite a bit.
"Blood and piss come out of there. Blood and Piss."