To be a literal phrase, "tattooing [on] the vagina" seems difficult to practice. It would be more believable if it referred to "tattooing [a design of] the vagina," though it's still complicated. On the other hand, as a locution, it can be interpreted as "marking a man to a woman (in a sexual sense) as one's own", as explained by colleague Iván Higuera. See vulva .
