During tango parties/ events also called milongas there are certain rules that most tango dancers adhere to or the codigos de tango or étiqueta de tango : tango etiquette, customary behaviour, unwritten social rules, may vary from milonga to milonga, from place to place, and time to time.
The aim of the codigos is a safe, respectful and harmonious event, where most people have a pleasant time.

Here is an overview of the unwritten tango social rules:
Line of dance or ronda
The general flow, ronda or line of dance of the dancers in a milonga is anticlockwise around the room (like a car). It is respectful not to overtake and to stay in your own lane like when driving a car, also no sudden stops. Recommended is for leaders when entering the ronda to make eye contact with the leader they want to zip into before and wait for them to give you space. NEVER cross the dance floor or stop to chat. And usually it is not accepted to teach during the milonga. Chat is for during the cortina (curtain) or break between the tandas. A tanda is a series of 3/4 songs that you commonly dance with the same dance partner.
If Hagrid can do the cabaceo – so can you!
Cabaceo
A cabeceo – is a respectful way of inviting someone to dance. It is an unspoken invitation by the leaders and acceptance or refusal to dance by the follower. It is essentially a subtle nod, look or glance which is acknowledged equally subtly by the follower’s mirada which means look or can be a nod, if the follower is not interested they will look away. The cabaceo is intended to avoid coercion, obligation, embarrassment or other discomfort by either party. It is not forced.
For followers if you like to dance with someone just look at them and try to be present/ visible, walk past and make eye contact. Also, highly recommended is to treat this as any party and socialise, a milonga is a social event after all. Chat to many different people so you have fun and the more you get to know people the more likely it is they will invite you sooner or later to dance as well.
Personal hygiene
As tango is a close contact sport for most people it is obvious that personal hygiene is very important if you wish to be popular. So, bathed or showered body, and washed clothes, brushed teeth. If you sweat profusely, it is recommended to take a towel/ handkerchiefs. Recommendable is to take a clean shirt and change into it half way through the evening.
Dress code
Dress code may or may not be important. e.g. no jeans and shorts, it is recommended to check with the organisers or regular visitors what the usual dress code is. Some milongas are quite formal and they appreciate a smart dress code.
Tandas and cortinas
At milongas tango music is grouped in tandas as discussed before they are a series of 3/4 songs with cortinas (non tango music breaks) in between. Normally, you dance after the music has started to see if the music inspires you and if you are a beginner, to see if you are able to dance to it. So, if you are leading you should cabaceo at the start of the tanda not during the cortina. There are 3 music sub styles in tango; tango, milonga and vals. Most of the milongas have tandas structured like this: T, T, M, T, T, V and repeat.
During a live music concert it is common to appreciate the music first and after invitation from the band leader you start to dance.
It is polite to dance the whole tanda with the same dancer. If you are not sure you could invite someone during the last song of the tanda. If you must break off earlier during a tanda then do it at the end of the song and just simply say thank you no explanation necessary. At the end of the tanda, be careful how you thank your partner as some people might understand it as Thanks but no thanks! So be really clear and perhaps say something like: “I really enjoyed dancing with you” to avoid misunderstanding. After the tanda the leader is expected to bring the follower back to their seat/ or place where they were at time of the cabaceo.
Finally at Tango E14
At Tango E14 we are not that formal and are fine with people asking as if in a ballroom/ tea dance setting as most of our dancers do both Argentine tango as well as Ballroom dancing. These codigos or rules are for other more formal milongas. Best is to observe first and do as the Romans do…!