Proper clarinet embouchure presents a pedagogical conundrum simply because the many forces involved cannot be observed visually, and many pedagogical resources state conflicting opinions often based on subjective "feel" rather than any empirical data. In order to broaden our understanding of clarinet embouchure dynamics, seven professional clarinetists were asked to perform various tasks using thin-film force sensors to measure embouchure and thumb forces. The results indicate variations in how clarinetists apply embouchure forces during performance.