Castle is not a stripper! He makes this point well known in this preview for the episode "Almost Famous," which centers around the death of a stripper.
Beckett's former partner returns on this episode, while the action takes place at a graveyard. Watch this promo and get excited for "Under the Gun."

Castle Season 3 Quotes

Castle: How do you know when you're in love?
Beckett: All the songs make sense.

He really is ruggedly handsome.

Ryan (looking at cutout of Castle)