Had someone take a look - not a lesson, just a look. Most of the problem is due to my off-center positioning. One of my upper incisors is turned just a hair, and that causes me to sound and play much better off-center. Over the years I had probably slowly shifted as my teeth changed, and that's why the "problem" didn't show up until later in life. Playing centered now sounds horrible. I had noticed that the mp ring on my lips is shifted about 1/8" off center (i.e. not a lot, barely noticeable while playing), but didn't think about that being related, even though almost all of the leaking occurs on the short side. Duh. Solutions offered? Fix the tooth (which is not a visual problem, it only affects embouchure), which will probably ruin my sound, at least for a while. Work on strengthening the embouchure, which is good advice for anyone at any stage with any problems (or none). Try a mouthpiece with a wider rim to support the "short side" of the embouchure corner a bit more, though I'll have to be the judge on its impact on the rest of my playing. Slowly nudge the mp back towards center during practice, paying close attention to the tone and position... eventually I might be able to nudge it back enough to help with the leakage without sacrificing other aspects of my playing. Final suggestion given : since I'm not a professional and don't aspire to be, determine whether it is bothering just me or affecting my performances. If no one else notices, then perhaps there is nothing to fix, other than general strengthening and getting the chops back into better shape, which would probably a little help anyway. Thanks for the other suggestions here. I'll try to dry the lips more and see how that works. The leakage is at its worst during extended multiple-tonguing passages when there is more spit and more wetness on the lips, so that makes a lot of sense. And I'll probably use the pencil training thing as part of my general "getting back into shape" routine, as well as the suggestion of working on endurance by playing until leaking starts and then taking a break. Since the problem first appeared in college when I was playing consistently and the chops were in good shape, I may not be able to eliminate it completely with strengthening alone, but any improvement is welcomed (especially if it comes "for free" when working on better playing in general).