Sorry about my late reply, have been of net for many months.
Milonga and its unwritten rules.
When I first came in to a milonga I felt a little uncomfortable at first. Being blond and entering alone, I felt that all the argentin men was staring at me. Well, I did not know the rules.. Once I understood, it was great fun. Here is a summary of what I was told by my argentinian friend and some stuff I picked up by experience...
*: A lady that is entering a milonga alone, means that anyone can dance with her.
*: You do not walk over to a lady/man and ask for a dance. You make eye conntact and wait for a response. A response is either a smile or a nod. Then you walk over and bring your partner to the dance floor. (this is actual practical - especially in large rooms.)
*: A lady can ofcourse 'ask' a man to dance
*: Never start dancing as soon as the song(music) starts. Wait a minute and have a short conversation with your partner. This is an old tradition, when young single ladies where escorted by an older family member to the milonga and they were not allowed to spend any time with young single men alone. The only oppertunity to have a private conversation was on the dance-floor, but you should not dance and talk at the same time. So, you talked a little before you started to dance.
*: Never put your dancing shoes on at the table. Use the restrooms or wear them entering the milonga.
*:When a couple is entering the milonga together, you can not egage the wife unless the man is occupied dancing with another lady.
*: There are periodes of dances, usually 4, and then there is a break. If you are not sure if you wanna dance many dances with a particular partner. Start when song nr 3 is playing. You are supposed to dance the period out.
*: If a man entering a milonga with more that one lady, no men can engage the the ladies util the man who brought them there is dancing.
*: If you are single, never go out dancing on a saturday night. This is the day when husbands will bring their wife to a milonga and dance only with them.