I only know of one scene to be honest, and it was actually my introduction to felching. The scene in question is Lucas Entertainment's "Bulrog Takes Command of Ace Era and Michael Roman". At first it kind of put me off, but now I find it super hot!
Just checked it out and got rock hard immediately.
If you want felching videos that will make it impossible not to nut, check out the 3 or so Ultimate Gay Felch Compilations. Amazing.