Sorry to bring this up again, but I’m having some trouble with the search function.
So…what’s the trick ? I seem to be doing triplets well by alternate picking, but not cuts and taps. 
I do cuts between notes of the same pitch with a really quick hammer-on/pulloff, sort of a left hand pizzicato. You can also put a cut in front of a note by picking the note above and pulling off quickly. Just like on a flute or whistle, the pitch of the note you’re cutting with doesn’t matter too much since it goes by so quickly.
Roger Landes taught me a really cool roll-type ornament that uses this technique. Pick three eighth notes, DA DA DA, and divide the first note with the hammer-on/pulloff thing so it becomes DIDDLE DA DA. It’s a lot more relaxed (and easier on the ears imho) than doing picked triplets all over the place.
The only thing I do on fretted instruments that you could call a tap is picking a lower note and sliding immediately up to the “real” note. I don’t use this the same way I use taps on the flute, though.
thanks for the info! I really appreciate it!!!
I do similar things to Ro3b. I do rolls on certain notes: say a note at the second fret by cutting with the note at the fourth fret and tapping by pulling off to the note on the open string and hammering back on immediately. On the whole, I prefer to use ornaments that suit the instrument than to decide in advance which ornaments a tune should have and then force them onto an instrument. So bending up works well on guitar for example, but on harmonica you have to bend down unless you can start a note bent and then ease it back into tune which is much harder. On concertina, for example, I wouldn’t use rolls much if at all, even though they can be done. I’d rather use triplets and and certain staccato tricks with the bellows that give the same rhythmic effect as rolls but sound better to my ears.
I think you can worry far too much about ornamentation if you happen to play (as I do) an instrument on which the possibilities are limited. The main thing for me is to play clean and rhythmically. Variation is quite important, and some limited ornamentation is possible, but it don’t mean a thing if you ain’t got that…nice, bouncy drive and rhythm in your playing. You can (for megabucks) buy a harmonica direct from Brendan Power that is specifically set up to play ornaments. It bears little resemblance to any standard harmonica that you can come by in shops. Well, I’d rather use a standard (or, at most, lightly-tweaked) instrument and do what I can within its limits. Otherwise I feel that the tail is wagging the dog, to coin a cliche.
Cheers!
Steve