A typical sequence of events when enjoying a BDSM session is as follows (in this example, as a masochist):
This is a standard sequence.
However, an important qualification is that there can be a delay between steps 3 and 4.
Often this delay is so short that it is barely noticed, and the perception is that, for example, having your nipples twisted by your partner is a pleasurable experience.
However, in some cases there is a noticeable delay, which may be seconds, or even minutes.
When there is a delay, it is more obvious to you (the masochist), that your conscious decision to passively accept what your partner is doing to you is essential to your eventual enjoyment of the session.
This suggests a hypothesis about the difference between those who are kinky and those who believe themselves to be completely "vanilla":