I'm the wrong guy to ask whether this is NSFW, so just have a link.
I'm gonna say "not safe for work, but safe for those with an open mind who understand it's just a cartoon and that that particular gag's been done a thousand times before. And it's safe because David hasn't edited out the link yet."
And why do I like that little heart thing wazeling (yay, made-up word) near his head in the last panel? I've seen that quite a few times in furry artwork, but I don't quite know what it means. Strikes me as a love-lite thing given the heart's small size, like "you're a cutie, love ya". Must be an anime thing. Or maybe it's the anime version of heart thumping out of chest.