When I was a teenager a group of friends and myself used to hang round in the city centre, as you do, in a green place where there were lots of other teenagers and a few alcoholics.
There was one of said alcoholics who everyone knew and he'd wander round the groups of kids sitting down and having a chat. He was always an affable chap.
On one occasion he offered his bottle of cider round the group, we all declined except for one of the lads who felt a bit bad that we'd all declined this generous offer.
So he took a swig from the bottle, hesitated, swallowed and looked a bit green.
It was later that he told us when he'd taken the swig, there was a "slimy lump" in it.
We were nearly sick. It was gross and nearly 20 years ago, but I still remember it vividly! 