I don't think there is much harm in asking how SA is? None of the rest of it thought and only do it if you think you can hold back and not get involved. You could try 'How is SA?' if he makes another initiation. No more than that though, when he answers just say something like 'cool glad you are having a good time' or whatever. Keep it light though, you want to be friendly and express an interest, just not too much. :-)
