This is a game where one's friends get in to a small group and form a circle and all start to wank over a chocolate biscuit the last to come loses and must eat the biscuit
This could possbily make the loser very ill but a friend of mine who did it lost and had to eat the biscuit and he said man come tasted salty!!
a limp, moist, weak, handshake
As in a man or woman gives you a bad handshake. "I sure don't trust that guy Bill, he gives a wet biscuit." (i.e. bad handshake)