I recommend the glass bong straws from my signature.
this is the etsy shop
https://www.etsy.com/people/HumboldtCountyGlass
It looks like you have to special request them (after etsy policy changes a while ago)
but it's a glass piece that sticks in your (either 18 mmor 14mm) downsteam and is a flat or divoted paddle with an airhole, they can make one so it turns color when at the right temp too.
basically you heat the paddle that's attached to the bong and the other paddle, when they get hot you mash a ball of hash between them. Works like hot knives but with water filtration.
This is the only pic i found easily
https://www.etsy.com/listing/48200950/glass-hot-knives-cupped-bong-straw-and
This is of one of the divoted non-color change ones, pic only showing the piece that goes to the downstem, not the other paddle.