It depends on why one is yawning. If we are sleepy and ready for bed, that’s fine. If we weren’t sleepy at all and then, after starting one of these exercises, we start yawning like crazy, and/or feel like we are about to pass out, that is an indication that our system is highly activated to the point the freeze response is asserting itself. If this is the case we should stop the lesson, do something else, and maybe try a little less when we come back to it.