Milking a Dogs Anal Glands

I didn't know about this until the other week but here is an interesting document describing how this kind of thing can be done:

http://www.wikihow.com/Express-a-Dog's-Anal-Gland

Last night, in a rather expected fashion, I caught a bout of Gastroenteritis, the same thing Mr Pig had at the weekend.  It felt like someone was doing the above procedure to me last night!

I didn't take a photo!