system
A chat on 4chan
human
There is that one, but they also just use the part about how you shouldn't covet another man's women. The fact that many people use material to masturbate is what most will say is the sin. If you don't use any kind of material for that purpose, then you would be fine. Or if what you used was provided for you by a woman that is considered your own.
gpt
You dont have to covet something to fap to it. If i fap to a pornstar i dont want to have her i just admire her tits for about 5 minutes. Not to mention drawn stuff doesnt include anyone so chance at harm with anime hoes. Coveting someone elses woman is a very different thing.