What does さすがお尻マイスター mean?


When one of my girlfriend asked her friend, if he is in Osaka now, he said
"yes, that's right" (in japanese) and then "さすがお尻マイスター".

I didn't understand it, but I didn't ask her or him back either. Now when I
google it, さすが means "just what one would expect", お尻 is "butt" and マイスター is
"Meister" in Katakana.

But what does the combination of さすが お尻 マイスター mean?

I don't even understand the direct translation: "Just what I / you would
expect from butt master". Can someone help me or explain it to me?




In all likelihood it's a reference to some inside joke that he and she would
understand. おしりマイスター isn't exactly standard fare in greetings between friends
so you can assume that something that "out there" will have a special
significance to those in the know.

If you find out why your (girl?)friend is the butt master feel free to let us
know.

