I've seen it twice in porn, once by Ashley Coda, and once by Jenni Lee.
The guy is sitting down in a chair. The girl faces straddles his legs, facing away from him. She bends at the hips and sucks his dick, while the guy either enjoys the view or decides he needs a snack, too.
It's probably not a really easy thing for a woman to do for very long, but, visually, I find it very stimulating, especially when the woman has legs like Jenni Lee.
Is anyone aware of a name for this? If not, care to invent one? "Standing 69" come close, but it's usually applied to another position.