While sternal rubs do work, they aren't as preferred due to the high tendency to bruise (at least for medical professionals, since you have little issues like lawsuits...)
For central stimuli, applying periorbital pressure or squeezing the trapezius muscle is usually done, though if you're fine with peripheral, the accepted way is to place a pen (or other hard object) at the base of two of a patient's fingers or toes and then squeeze the fingers/toes together against the object.