Which IEMs are you using? I have very similar issues, and I have found that found that the shorter the stem of the IEM, the worse this problem becomes. The only way I have ever been able to even remotely get most IEMs to fit is by having to basically cut my own stem-lengtheners from silicone tubing, or by using extra long-stemmed ear-tips. HOWEVER - the only IEMs that don't give me the same problem (so far) are my two pair of Etymotics, using their newer dual-flanged silicone tips. In fact, I don't even need to use their largest eartips, because their IEMs are very small, and are made to be inserted very deep. I have found that the deeper the IEM insertion, the better the seal for me, because this way the ear tips make contact with my ear canal where it is the narrowest. Despite needing the largest tips for pretty much every other IEM I have ever used, I can get away with the medium dual-flange Etymotic tips, when used with their IEM. I would imagine that if I tried the same tips on a shallower fitting IEM, I'd have the same problem that I do with all the others.