How to write GREAT SMUT

Hi, so I'm writing a fanfiction and its doing great hehehhe, but I don't know how to write smut. I used the tag "smut" without actually knowing how to write one. I don't want it to be awkward and show how inexperienced I am ( I never had sex and I don't write smut, but I do like reading yaoi hahaha).

Or else I'll only be able to write the overused:

"They were connected by a string of saliva"

So any tips? Thanks in adavnce