WHAT IS A LIMIT?
A limit defines the boundaries within which a player might choose or not to choose to engage in certain types of play. In the play pre-negotiation period, talking about limits is simply courteous and allows all plays determine what they would like to explore within play as well as anything they do not desire or will not tolerate. The best way to think of a limit is to think of the origin word: 'limitation'.
It is important to note that limits do vary from partner to partner and are fluid - ie. they may not remain the same for an individual each time they play, and are (or can be) largely dependent on psychological and physical factors occurring around the time of play. The conversation about limits should always occur in the pre-negotiation and consent communication stages before play.
Limits can be 'soft' or 'hard' and each of these have separate meanings. We're going to look further into soft and hard limits, as well as the concept of 'no limits', below.
SOFT LIMITS
A soft limit can be defined as something that a player communicates they do not normally wish to do, but that they may consider and consent to exploring it (with strict negotiation).
For instance, a player might not consent to a specific type of play in some circumstances but may allow permission to engage in said play under specific conditions. This could be - and is often - extended to types of play that one might require a greater level of caution when approaching.
HARD LIMITS
A hard limit is an action that a player indicates they do not want to engage in at any point and that they do not consent to. Do not attempt to broach any communicated hard limits.
NO LIMITS
The topic of 'no limits' is quite controversial within the BDSM community. How can there exist such a thing as 'no limits' if, theoretically, the only way to prove that there are 'no limits' is to kill or be killed? Some believe that claiming to have, or utilize, 'no limits' shows a understanding of BDSM in practice.
Those who choose to identify with 'no-limits' within their dynamic or play sessions usually, in reality, fall under the umbrella of consensual non-consent - and generally have some sort of humane understanding of basic respect. Even in more intense TPE (total power exchange) situations, it is expected that both the top/Master and bottom/slave take on the responsibility of communicating clearly about what is permissible.
REQUIREMENTS
Sometimes play will have requirement limits. These are things that must happen, no matter the circumstance. Requirement limits can be anything that any of the players involved will not participate without it being present.