What is meant by the phrase "Oh, Matron!", when used as an exclamation?

It’s in reference to the comedy “Carry On” films. It’s one of the famous punchlines.

http://www.imdb.com/title/tt0064133/ should help you out there’s loads of films. It’s unlikely he literally thinks of you as “matron”

In the movies a Matron is a very senior nurse.

Matron was the title given to the senior nurse in charge of the nursing staff in hospitals in the UK before we went all modern and had managers. She ruled with in an iron fist and would inspire fear and awe from the other staff (doctors included – you did not fuck with matron).

I have never heard the phrase and, like you, would have no idea what the person might be implying.

Actually that’s “A Patrón”. It’s a directive to a bartender for another tequila.

Is this how he says it?
Plenty of related “Carry On” clips listed alongside this maybe you will find the one it comes from

Yes. That is how he says it. I’ve been watching some clips myself. Apparently this is a campy comedy made before I was born.

I am still a touch confused though. From what I can understand, the “matron” or head nurse is a homely and very stern and mean supervisor. If he means I am like that, then I am definitely not amused.

No It just means “Oh help, get me out of this!”
Does he do it when you are disagreeing and he feels you are being obtuse?
Why not ask him why he says it?

Oh. Well that makes sense. He does it occasionally if I say something playfully flirtatious. If he wants “out of this” I guess it’s my cue to stop.

Ooh Matron, is said when one is sarcastically showing surprise at a saucy comment