Legal Age of Consent in Arkansas: 18 and 14 – No Problem, But Keep Your Clothes On!

From Kidd v. State, decided today by the Arkansas Court of Appeals, in an opinion by Chief Judge Brandon Harrison, joined by Judges Rita Gruber and Kenneth Hixson:
The court rejected Kidd’s argument that the exposure offense is unconstitutional under Worsham:
My question (besides noting the absurdity of a state scheme that allows sex but criminalizes showing genitals, including during sex): Was there really enough here to prove, beyond a reasonable doubt (at least based on the quoted testimony), that Kidd exposed her vagina “[w]ith the purpose to arouse or gratify a sexual desire of himself or herself or a sexual desire of another person”?
M.C. testified that, when he said “she wanted it,” that meant “she wanted to have sex.” He didn’t testify that Kidd had the purpose of satisfying the sexual desire through the exposure of her genitals; the exposure may indeed have been just functional in the sense of that it was convenient to having sex, which is what gratified sexual desire. (It’s certainly possible that she also got turned on by showing her genitals, or wanted to get M.C. turned on that way, but I just don’t see how that motivation was proved beyond a reasonable doubt.)
Or is the court’s implicit view that, to “purposely expose[] … sex organs” with “the purpose to arouse or gratify a sexual desire,” it’s enough to expose them just as a step towards having sex, even when the sexual gratification would come entirely from the sex and not the exposure? If M.C. and Kidd had made clear that neither was trying to turn either on by watching, but were solely interested in doing, would the crime of indecent exposure to a 14-year-old (with whom Kidd was lawfully having sex) still have been committed?
Joseph Karl Luebke represents the state.