From bowiki

Originally from a Bodojo post by Kip

There is not double ended TRIPLET! it is not a triplet. if anything it is adding one 16th note between 2 eight notes.

1 + 2 + 3 + 4 +

1e+ 2e+ 3e+ 4e+

now..when folks do a roll, they speed these up, and often change the accent so it sounds like your are doing multiple groups of sextuplets