Everyone views it differently, but I wouldn't say it's creepy, per se. Well, maybe a little, but if the thought of your friend pops up in your head while you're fapping, or you're scrolling through pictures and they look particularly hot in one, or something like that, I'd say it's alright. If you have a friend who is not interested in you, but you are interested in them, I would say that fapping is a healthy way to get those feelings out while still respecting their interest, or rather, lack thereof. If I found out any of my friends fap to the thought of me, whether I'm interested in them or not, I wouldn't care. And even if I was interested in them, I wouldn't assume that they were interested in me just bc they fapped to me, because people do weird things when horny. Now, if you are actively perving on them, that's weird and creepy. But if you respect them as a person and respect their decisions, and just treat them well, and just be friends when you're around each other, then I think it's fine.