here is an article with the Cambridge rules
www.bbc.co.uk/dna/getwriting/A882722

Oxford rules are slightly different and Teddy Hall generally plays 'hand on glass' where you can only be pennied whilst touching your drink.
( WormuIus, Thu 11 Sep 2008, 12:15, archived)

You can only be 2p'd when the drink is in your hand
that's the main rule.
( Master Of Turnips. Only gays and morons believe in ghosts., Thu 11 Sep 2008, 12:16, archived)

I've played with people from other colleges and universities who don't use that rule.
but its a good rule to have imo.
( WormuIus, Thu 11 Sep 2008, 12:18, archived)

I will end by adding
that if you dropped a 2p into the pint of anyone I knew who was aware of 'pennying' they would make you drink the beverage in question for using a 2p instead of a penny.
( WormuIus, Thu 11 Sep 2008, 12:18, archived)

I have just showed this thread to TFS
who wholeheartedly agrees with me.
( WormuIus, Thu 11 Sep 2008, 12:20, archived)