The real-world cousin of the Vulcan nerve pinch, carotid sinus massage is used diagnostically to evaluate vagus nerve function and therapeutically to control tachyarrhythmias. The carotid sinus is found at the bifurcation of the common carotid artery (just lateral to the thyroid cartilage of the larynx), and contains baroreceptors which normally sense blood pressure (together with similar receptors in the aortic arch). In normal people, massage of said sinus results in bradycardia (and hypotension)—the baroreceptor reflex, which normally acts to correct rapid changes in blood pressure (eg the drop associated with standing suddenly, in which case the reflex acts to increase the blood pressure).
It is potentially quite dangerous, and should not be attempted outside the hospital setting. Acutely, bradycardia, hypotension and heart block may occur; in the presence of atheromatous vascular disease, plaque fracture and embolism may result in stroke.