If I were to make a bong with a water bottle, how would I go about making the bowl?

I've read using a pen to connect the bong to the bowl, but what could I use to amke the bowl?
poiuyt Reviewed by poiuyt on . Making a bong...?? If I were to make a bong with a water bottle, how would I go about making the bowl? I've read using a pen to connect the bong to the bowl, but what could I use to amke the bowl? Rating: 5