Petrie: (In a really low tone, so Spike doesn't hear) Me love you Ducky?
Ducky: (Also in a really low tone, so her brother Spike can't hear as well) I love you to Petrie; yep, yep, yep.
Spike: (Thinking) Aw, isn't that sweet, I just knew my sister Ducky and Petrie were in love and together!