Captain Mal Reynolds is not a man of fancy: he knows that lips taste like lips and whores' lips taste like fancy bonbons and desperation. Inara tastes familiar because she's absorbed his Serenity, and because he's not done did for ages and because he misses home, a little bit sometimes, the grass and the sunshine, and sunshine doesn't taste like anything, so clearly he is projecting, projecting his wishes right into her mouth, and what right does he have? He doesn't want to be her next, most fucked-up patron, using her like an empty pad of paper to sketch his desires.