Chandler: (coming from the guest room) Hey, Mon. I think I figured out whose handcuffs they are.
Monica: You did? How?
Chandler: Well, I was cleaning out the closet and I found pictures of them... being used.
Monica: Oh, my God, let me see!
Joey: (looking at the pictures) Who's that dirty old lady?
Chandler: Monica's grandmother.
Monica: Oh, my God! Nana liked it rough!