When asked the inevitable, a kilt-wearing friend likes to say, "Just a touch of lipstick."
There is another, less known, what's-under-the-kilt song called "Angus" by Lolly Foy, sung by a duo with the admirable name Wench Work, whom I once traced as far as ?Michigan where the trail petered out, and also recorded on Celtic Folk Live Vol 4, particularly apropos to a knowledgeable audience since it involves the greatkilt, the one long length wrapped about, rather than the more modern stitched pleated one.