Hi, gallant sufferer!

I have my mustache since 1962 and play the harmonica sometimes, just for fun. I had the problem mentioned only once, then never more. I trimmed my mustache, it just ends above the upper lip. My wife prefers this style, too, instead of the overlapping version: a wonderful side effect is that it tickles better when kissing (you know, a kiss without a beard is like a soup without salt).
Another possibility is to change from harmonica to treble recorder (there are some very small ones).

Wilfried