Argentine tango codes were established organically over a long period of time in order for the community to meet and interact smoothly so that all may enjoy each other's company and the pleasure of dancing.
The Line Of Dance
While dancing, couples should travel counter clockwise, moving forward in the line of dance.
The line of dance has lanes. Dancers travel counter clockwise on the largest circle that will fit in the room. If there are many couples there will be an outside lane as close to the edge of the room as comfortably possible, and within that another concentric circle of couples also traveling forward counterclockwise. If it is very crowded there can be a third inside circle, also traveling counterclockwise.
Couples should stay in their chosen lane and not switch from one lane to another, nor should they pass the couple ahead of them.
When entering the dance floor, leaders should make eye contact with the leader who will be behind them so as not to surprise them by suddenly jumping in front of them without warning.
Above all couples should dance in such a way that they are in no danger of interfering with the dancing of other people. There are no excuses for running into, or kicking, or stepping on any one else while dancing. If a collision does happen, it is always polite for the dancers to apologize to each other whether or not it was their fault.
Milonga Guidelines
The music is usually organized into groups of 3 or 4 songs of roughly 3 minutes each called “tandas” and the tandas are separated by 20-45 second “cortinas” which are recognizable as they are non-tango music.
It is expected that the dancers will complete the tanda with their partner, while the cortinas provide a break for the couples to chat, separate, look for another partner, get a drink, etc.
There is usually a 4 second or so pause between songs. A little compliment or comment lets the partner know that the dance is enjoyable, but “thank you” is reserved for the end of the tanda when the couple separates, so resist the urge to say "thank you" unless you want to stop dancing with your partner.
Milongas are for social dancing. Teaching overtly during a milonga is distracting and can be disruptive to the flow of dance. Prácticas are appropriate tango events to attend if you want to teach while dancing tango.
Never walk across the dance floor while people are dancing. Take care while walking around the outside of the dance floor while people are dancing. If possible, wait until a break in the music to walk next to the dancers.
Try not to talk while dancing. It can be very distracting for the dancers around you who are focusing on the music, each other, and the dance they are creating together.
The “cabeceo” is an invitation to dance by using only a look and is considered to be the most courteous and efficient way of inviting someone to dance. Usually it is the leaders who initiate the invitation. The leader will attempt to to catch their intended partners eye by gazing intently at them. If the gaze is returned the leader will do a quick head nod or glance towards the dance floor and if they receive a little nod and smile in return, they will approach the partner and escort them into the floor. The follower may provoke the invitation of their intended partner with their “mirada” or gaze/looking. This is accomplished by the follower looking at the person they wish to dance with.
If the recipient of either the cabaceo or mirada does not want to dance with the person offering the invitation to dance, they will avoid making eye contact. No one should feel forced to dance with anyone for any reason. If the invitation to dance is verbal and the recipient of the invitation does not wish to dance a simple “No thank you” is polite but clear. But if the recipient does want to dance at a later time, adding “but please invite me again later (after I’ve rested, or finished this conversation, etc)” communicates the desire to dance at a later time.
Tango is sensual, emotional, expressive but there is a line between the intimacy of the dance and behavior that takes advantage of that intimacy and pushes into the realm of creepy! If a dancer feels that their partner’s behavior is making them uncomfortable they do not have to continue dancing with them. One can choose to say “I am not comfortable with this” or can stop dancing, say “thank you” and walk off the floor. If you do this, you will be communicating beyond the shadow of a doubt that you have found your partner's behavior to be unacceptable.
Couples who arrive and leave together will often dance at least the first and the final tanda together. Pay attention to the couple and respect their wishes to dance certain tandas together. All the other tandas in between the first and last are up to their mutual preference. If you want to dance with someone who is in a couple, it is important to take care because they may be dancing with only each other. If you see one or both of them dancing with other people, it is acceptable to invite but is a good idea to use the cabaceo rather than verbally inviting.
Good personal hygiene and generally courteous behavior are expected and make everyone’s experience better.
A friendly and curious attitude go a long way towards making the milonga a wonderful place to be.