Puck's inability to speak may or may not be a rarity. Usually, he chooses his words carefully. He's a man of few words, and - when he speaks - he makes it count. ["How many balls can you fit in (your mouth)?" was a perfectly acceptable use of words, by the way.] He's the king of dirty talk in the bedroom, though, but now? Now, he's just quiet, because he can't speak, because he can't think, because everything Sam's doing is short-circuiting his brain.

He makes a high-pitched noise halfway between a whine and a scream when he feels the vibration; that's clearly the desired effect, and he arches his back, hips bucking against Sam's body as his cock jerks.