Quote from Chandler in The One with Phoebe's Cookies
Monica: Hey. How was it? Ross: Well, I had a great time. Chauncey on the other hand... Chandler: I will tell the story. Well, it was going great. I let him win, we were bonding. He even said I could call him Dad. Ross: And what did he ask you not to call him? Chandler: "Daddy."