The salon girls don't care whose nails they manicure, in fact it'll give them an 'oh my goodness!' tale to share with girlfriends after you've taken your sissy to have hers polished in public. They'll think she's gay, so tell her to talk about a boyfriend - explaining it's for their comfort. She'll be terrified the first time, and must dress fully as a woman, but eventually she'll love the pampering. Have her agree once they urge her to book regular appointments to stay pretty.