First for me... what's proper etiquette?

I was walking past the Alladin closed shops at around 4 AM this morning on the way back to my car as I approach these two asian girls. They look to be completely touristy with their camera out, etc. Anyway, I am walking past and it looks like one of them is trying to ask me something, but doesn't know how. I assume she can't speak english very well so far by my read and try to give a signal to take a picture of them together because that is what I thought they wanted.

It was and they handed me the camera and I did the usual. Here was the odd thing. Afterwards, the cute one goes over to me and gets the camera. She tries to ask if she can be in a picture with me before I left. She hands the camera to her friend and I get ready to pose with this complete stranger. What's my move?

I wasn't sure what stranger picture taking etiquette was, but didn't want to press my luck, and decided it would be best to keep my arms by my side instead of going for the around the neck. As she moves in however, her tight ass slips by my hand. This was clearly an accident by me and she looks down at my hand, than at me. She smiles and we take the picture. My move? And how have I played it so far?