knife hits are awesome. You don't need a glass bottle, though. Just take a normal plastic bottle, cut the bottom off, then turn the bottom back upside down with a few cubes of ice in the empty space there. You can use tape (make sure the bottle is dry) to seal it. It does need to be slightly air-tight. Keep it in the freezer, that way the ice won't melt and you can re-use it.

Knife-hitting hash floors you, or if you take a little ball of bud and roll it in some keef (helps if it's some sticky shit). I took a couple hits like that and that got me higher than I've ever been before. I've actually never been as high as that time. A lot higher than the hash, actually. damn.