The pure joy of dancing tango socially is found at the Milonga (a place where Tango is danced socially).
When Tango is danced socially good floor craft and respect for other dancers on the 'piste' (dance floor) is essential. High leg kicks and hooks (favoured by stage tango dancers) are not used (or kept to a minimum and cautiously) on busy dance floors.
What is a Tanda?
At a milonga, music is played in sets called "tandas." Usually three or four songs are played by the same orchestra followed by the "cortina" (the interval) which is usually between 30 - 60 seconds long and signals the end of the tanda. If you ask someone to dance and they accept, it is assumed that it will be for the entire tanda.
Cortinas are an interesting little detail at a milonga. A cortina is unique to each DJ. Some will select one cortina for an evening and some will use a different one for each tanda. Some are humorous; some are grating on the ears; some are simply beautiful music. In any case, the cortina is supposed to be a piece of music that people know not to dance to. It's your signal to smile, say thank you and (usually) change partners. Even if you are not changing partners it is good practice to get off the floor during the cortina and re-enter when the next tanda starts.
How Someone Asks for a Dance
In Argentina and in many milongas in Sydney, men ask women to dance with the 'cabeceo'. The cabeceo is an invitation with the eyes, a certain glance and movement of the head and a smile that says, "Do you want to dance with me?" The cabeceo can take place from far across the room if the right eyes are caught. If a woman wants to accept a dance with a man, she uses the 'mirada' This means she accepts the cabeceo with returned eye contact and a smile that says "Yes I want to dance with you". Once she has accepted the invitation via the mirada it is most important that she keeps looking at him while he approaches her. The slightest glance away is usually interpreted as meaning " I've changed my mind" or " No, I agreed to dance with someone else, not you."
The cabeceo is an elegant and efficient way to give and receive dance invitations, but it does have its challenges. What if the asker is looking at the woman behind you? Did you really see a "yes" or a "maybe?" With more practice you become better at understanding the subtleties of the cabeceo.
This is how the cabeceo works. A man will look around the room and try to make eye contact with a woman. Also, a woman can initiate the eye contact as well. If she does not want to dance with him, she will avert her gaze. If, however, she wants to dance with him, she will make eye contact; he will then slightly nod his head in the direction of the dance floor. If she has decided to dance with him she will nod yes. Only at this point would a man go to a woman’s table and escort her to the floor. This prevents women from feeling obligated to dance with just any man who comes to her table and asks her to dance. Secondly, men are kept from looking foolish by going to a table and being refused a dance.'
Accepting or declining a dance invitation
Accepting a dance is as simple as saying "yes." You can do this with your eyes—be on the look out for people who ask the Argentine way—or by accepting a direct invitation.
It is also perfectly acceptable to say, "No, thank you." If you accept a dance remember it will probably last for the remainder of the tanda that is playing—three or four songs if you start at the beginning. If either one of you decides that one or two dances is enough, however, either person can simply say "thank you" and begin leaving the dance floor. Once you say "thank you" to someone in a polite manner, the dance with that person is over.
Dancing at a Milonga as a Beginner
As a beginner, you'll either be eager to dance with everyone or hesitant to be seen as a beginner. If you're eager to dance, go for it. Just remember that tango is danced in lanes that keep moving and the more experienced dancers tend to stay toward the outside. If you're hesitant, I can guarantee you that everyone in the room has been a beginner at one time and understands how nerve wracking it can be to look around and see everyone gliding by when you only know three movements. Even someone who has been dancing for only two weeks longer than you have will look like they've been at it for years longer.
The way to become a good dancer is to show up and dance. As Woody Allen once said, "98 percent of success is showing up." Another saying goes that "to become a good tango dancer, you have to do the miles".
That said, it's also very instructive to watch Tango being danced socially. You can learn a lot about how to dance well by watching at a Milonga.