PN (huh? seriously? what kind of low-expectation-having motherfucker would name their kid that? why not name your kid Nighttrain-in-a-plastic-bag Jones?)
I suppose you could think of a bong as a sort of ditch full of dirty water from a drug frenzy.
ditch, gutter, drain
排 (eliminate) + 水 (water) + 溝 (ditch)
= 排水溝 (big ditch.)
big ditch. who cares.