Look, go find your gross anatomy skull, and put your thumb, or index finger, whatever you apparently palpate the lingula with, and grab a minute steak and lay it over the ramus and try again. I remember a classmate like you telling me that when he gives his IAB he "bumps the lingula" before injecting. As far as "trying it on a few patients", I have a little experience. You cant frickin palpate the lingula. My partner has been placing implants and doing sinus lifts since the 80's and he has never "palpated the lingula". If you could palpate the lingula, every frickin dentist would try before giving an IAB injection. Why? Because as far as I am concerned, there is nothing more frustrating than a patient who will not get numb. And guess where it occurs most? #18 and # 31. So, tomorrow I have 13 patients on my schedule. Let me estimate 1/3 are mandibular cases. I will try to "palpate" the lingula, and in addition I will use a long 27 gauge needle(which I have probably only needed a dozen times in the last 5 years) to make sure I can bump the hell out of the ramus and let you know how well I can feel the lingula.
In real life dentistry, I block the inferior alveolar nerve with a short 30. I usually dont try to bump any bone(thats when it hurts), aim off the contralateral premolars and go well above the occlusal plane. Missing the block is infrequent. Like Dr. Jeff said, when you miss, you almost always get the tongue(too low and anterior).