The only h-scene I've ever jerked off to was the Miyuki 4th wall break JOI scene from Totono.
I usually end up skimming through h-scenes despite always making sure to patch them in for any games that have them, but in this particular instance I felt like jerking off was an absolutely critical component of the experience.
Can you really claim to have experienced Totono in its entirety if you didn't masturbate and orgasm when instructed at that scene?