To add my opinion to an extremely old topic, in general conversation I
refer to the act of keeping multiple song effects active simultaneously as
weaving. However, I would love to use the terms once mentioned here of
'doublestop' and 'triplestop' and the like (by far the most appropriate),
if doing so wouldn't immediately prompt confused questions.

Which leads to, you know you're addicted to EverQuest when you sing the
first three measures of five different songs over and over and over.

Athren, anxiously awaiting the day he no longer has to his macro, /em the
locomotive runs by, 'Choo-choo!'