The phrase “no mames” is a colloquial expression in Mexican Spanish that can have a range of meanings depending on the context and tone in which it is used. It can be translated literally as “don’t suck” or “don’t suck it,” but it is not commonly used in that sense. Instead, it is often used as an exclamation of surprise, disbelief, or shock, similar to the English phrases “no way” or “you’re kidding.” However, the phrase can also have a vulgar or offensive connotation, depending on the context and tone in which it is used.

In some contexts, “no mames” can be used in a lighthearted, joking manner among friends or acquaintances. For example, if someone tells a ridiculous or unbelievable story, a friend might respond with “no mames” as a way of expressing disbelief or teasing. In this context, the phrase is not necessarily considered rude or offensive.
However, in other contexts, “no mames” can be considered rude or vulgar. This is especially true if it is used in a confrontational or aggressive manner, or if it is directed at someone in a position of authority or respect. For example, if a student responds to a teacher’s instructions with “no mames,” it would likely be considered disrespectful and rude.
Furthermore, the context in which “no mames” is used can also affect its level of offensiveness. For example, if it is used in a professional setting or in front of strangers, it may be considered inappropriate or unprofessional. Similarly, if it is used in front of children or in a family setting, it may be considered inappropriate or offensive.
It is also worth noting that the phrase “no mames” has different connotations in different parts of Mexico and among different age groups. In some regions, it is considered a more vulgar expression than in others, and among younger generations, it may be more commonly used as a casual expression among friends.
In conclusion, whether or not saying “no mames” is rude depends largely on the context in which it is used and the relationship between the speaker and the listener. In some contexts, it may be considered a harmless and playful expression of surprise or disbelief, while in other contexts, it may be seen as disrespectful, vulgar, or offensive. As with any colloquial expression, it is important to be aware of the cultural and social norms surrounding its use and to use it appropriately in different contexts.