The toilet paper/kitchen towel roll (cardboard tube) stuffed with dryer sheets (toilet paper covered in air freshener would do the same job) and blow hits into it, personally it didn't work for me, i didn't pack enough in and even when i put like 40 bog roll sheets in, it still let smoke out (i was blowing slowly as well). So i think it sucked.. but hey, if it works go for it
i used to do that back inthe day