meh.. dont waste your money on glass screens... just go outside and grab a pebble big enough to cover the hole
Snapping is either smoking snaps (a bowl the size for one perfect, large hit, that totally sucks through at the end) or pulling through the last hit on a full bowl. If you load snaps for people who don't know how to hit a bong, they'll pull them right through without burning much weed, but if you know how to do it it's one of the nicest ways to smoke, IMO. Even doing snaps, I admit, I wasn't always that clean, I have gone weeks or months, even when smoking heavily. But that was always with my percolated zumo, so there was a lot of water and the upper water would be relatively clean. But eventually I came to hate that and got very particular about changing it every bowl or every session, at least.
smoking 'snaps' like that (never heard it called that before) is great when you're smoking inside and don't want ton of smoke to linger. just pull it all through and blow the smoke out the window.