One Piece Chapter 612

[poopdeville]

By that theory you wouldn't be attracted to any sort of woman out of reach thus making fapping an impossibility.

That's a red herring. I specifically talked about the physiological aspects. There's no reason for Sanji to even fantasize, because the mermaid's sexual organs are TOO BIG to be useful in giving pleasure to a normal sized human. It is physiologically impossible for Sanji to gain any sexual pleasure from the giant mermaid. She is not merely "out of reach". Personality aside, she is sexually like a cat or dog -- an animal whose sexual organs are the wrong size for sex with a human.

We do know why anime characters get nose bleeds, right? http://tvtropes.org/pmwiki/pmwiki.php/Main/Nosebleed , just in case.