In what Star Trek episode did aliens assume human form and say something abut feeling a corporeal body again: "to feel the blood flow", "to feel the heart beat and lungs full of air" etc. (or something like that!)
This is from the original Star Trek, Season 2, episode 20; "Return To Tomorrow"
An alien (known as Sargon) inhabits Captain Kirk's body
SPOCK: And if he refuses, Doctor, what do you propose to do with your phaser? That is still Jim's body.
(Kirk convulses briefly, and the sphere has dimmed a lot.)
KIRK: Lungs filled with air again. To see again. Heart pumping, arteries surging with blood again. A half a million years. To be again. Your captain has an excellent body, Doctor McCoy. I compliment you both on the condition in which you maintained it.
SPOCK: What are your plans for it? Can you exchange places again when you wish?