^IV is the only way to get the most out of any drug but most users still feel the risk/harm outweigh the reward.
I don't think anyone here is going to know your friend's slang so I'm going to close this. The main R'sOA for this drug are oral, intranasal, rectal and intravenous and so if you want information on one or all of those, use the directory and/or search... There has been endless discussion on hydromorphone around here.
EDIT:
It has been brought to my attention by someone in your general area (HighonLife) that the term likely means mixing the dilaudid in water and snorting it like is commonly done as an IV-alternative with tar heroin.
I don't see why this would have many advantages over simply snorting except to dehydrate the nasal mucosa less and I suspect its more of a cultural practice in the area that necessary/practical but I'll open this back up for discussion.