I think it might be ecstasy, but I'm honestly not sure. Only other thing I can think of is maybe nitrous carts, but I don't think so. Which tells you how obscure a term it is, given I was about as bad a junkie as it gets, and before my ~4 year H addiction, used to trip almost daily on either shrooms, acid or ecstasy (which we always referred to as "rolls," "E," or "X," if in pill-form, and "molly" if powder/pure mdma). Maybe it's a common street term in a different country?