What to do:
Take one foot and cross it over your other foot, letting it touch the ground, symbolizing an arc coming to an end.
See? Easy peasy! I have only used this spell a couple times, but it worked like magic for me! Unfortunately, I always forget about it while on the receiving end of a heinously boring and long-winded monologue.
End a boring conversation using magic!
I learned this spell years ago, but I can't remember where. I have gone crazy searching my few spell books and everywhere online, in order to credit the source, but I can't find it anywhere. If you know where this spell originated, I would love to hear from you so I can update this post with the appropriate credit, and also so I can stop driving myself crazy with the not-remembering.