A Question of Sausage

“Sausage” is a bizarre word. Consider the following:

Last night, I had 4 sausages with my mash. I could've eaten another sausage, but then I would have eaten A LOT of sausage.

What’s the plural of “sausage”? Is it “sausages” or is it “sausage”?

P.S. It’s Monday – don’t ask!

Update: Uh… I do realise that sausage isn’t the only word that exhibits this particular behaviour, I just wondered what that behaviour is called. Oh, and sausage is a slightly silly word which helps.