Why I should not be allowed to speak in discussion classes, part the second

It has already been established that I have a tendency to derail any group conversation, but I don't think anyone knows how bad it would be if I didn't think before I spoke. Consider the following, and remember that "Pegasus" was my ultra-exclusive four-year college prep English class.

The Scenario in My Head
Prof: "Think about your best or worst teacher and tell me about him or her."
Me: "My best was Ms. Brewster, my Pegasus teacher."
Prof: O.o "Pegasus?"
Me: ^_^ "Yeah, winged horse husbandry?"
Class: o.o *crickets*

What I Actually Said
Prof: "Think about your best or worst teacher and tell me about him or her."
Me: "My best teacher was Ms. Brewster, my English teacher."
Prof: "And yet you are a Biology Major.."

Now if I could just catch myself in time for all the weird things I say.