The egg timer seemed like an amazing idea:

set an egg timer every time I get up to talk and all eyes are on me. When the timer goes off, I am done. End of story. I can go on and on. I love to hear myself talk. I often cannot shut up. This is not really conducive to my students’ learning, however much I might enjoy it.

Many teachers feel compelled to talk because they have a captive audience, so they prattle on about their personal lives or current events instead of engaging students in the topic they're supposed to be teaching.