Tie down or exhaust pipe.
I typically go for self-serve fuel because who wants to pay Full-serve price? That said at KSPB where I often fill up, the line guys or gals do a lot of RVs so they know the quirks, plus they're e more familiar with their pump and nozzle and so are better at keeping gas from dribbling (or gushing) all over my wing like I have been known to do. In fact the only damage ever done was by me when the nozzle slipped in my hand once. I do always look over their shoulder, mainly to ensure it's filled to the tab so my fuel computer will be accurate, and I remove and replace the gas caps so I know that that's done!