Elementary, Season 1

Watson:
I've got to go meet my friend soon. Are you going to be okay getting home by yourself?

Holmes:
This friend that you're meeting, when was the last time you slept with him? It's quite obvious it's a he and an ex-lover. You go out of your way to avoid gender and every time you talk about him you avert your gaze when say "friend." As to how I know it's not a current lover, your walk speaks volumes.

Watson:
My walk.

Holmes:
A study in Belgium showed that a woman's recent orgasmic history can be discerned from her gait. Yours would indicate it's been a while.

Watson:
Is it sad being wrong as often as you are right?

Holmes:
My advice: sleep with him. It'll do wonders for your mood.