Who could resist a topic like this? I mean really?
Twenty years of giving or getting oral sex is bound to have gathered some perspectice ;-) To be honest, I didn't mean to fic pimp, but read pretty much any fic I've written, and there will be some oral sex somewhere. For the perspective of the person recieving oral sex, I' suggest late in Redeem Me, Scratching The Itch, The Heat Series (stories 3 and 4), The Third, or Secondhand Robes The Epilogue. Those at least had moments where the sensation of recieving a BJ was covered to some degree.
That aside, when I write sex, I have the good fortune to be writing from memory, some of them fairly recent, but mostly fond memories of some of the most amazing people. A couple of old flames in particular left quite a mark on me, and I on them. At least all that effort added up to being able to write slash goodness well :-)
Hope the stories help, and good luck! Samayel