Some physical turn-ons: Giggling, lip biting, lip licking, blushing, intense stares, coy smiles, moaning, thighs around the waist, arms wrapped around my head, cheek stroking, fingers through the hair, nibbling and licking at the neck, sneaking up behind and kissing the nape of the neck, finger suckling, clawing and biting, caressing just about anywhere, Klingon sex rituals.
Some mental turn-ons: Mentioning how needy she's feeling, teasing that she was turned on earlier and got a bit wet and flushed for me (and would I please touch her down there), daring challenges of who can make who give it up sooner, revealing that she was too horny to hold back from masturbating, revealing that she was fantasizing about another guy or girl and that it affected her rather naughtily, begging to be punished, taking the initiative, speaking fluent Klingon.
Okay, the last one from both lists aren't turn-ons, but being a fellow Trekker is certainly a positive trait.
