Why? There's no buttcrack or exposed cleavage.
It doesn't bother me, but I think it probably should have a maturity block on it for the younger members of deviantART. If dA hasn't said anything about it by now, it is probably fine though.
Just seconding JavaBeanJohnny's comment; I'm perfectly fine with NSFW content, but this warrants a sexual themes maturity tag.
Sexual themes. I may be almost eighteen but I would like to be warned for what I am looking at.
kids use internet, might not be naked, but is very.... eh