Overly intensive self gratifying procrastination, thought and contemplation for a subject not necessarily warranting such effort.
"Let's quit the mental masturbation here, its a waste of time..."
Rhyming slang... sausage roll... the dole. i.e another name for the dole or social security payments.
"I fear this recession is so bad, I'm terribly afraid we'll end up on the sausage roll"