This textual description that indicates that a man has had a vasectomy. The implication is that since a man is now supposedly incapable of getting a female pregnant that a condom does not have to be used.
Consider that if a condom is used, whether the man has had a vasectomy or not, getting a female pregnant isn't an issue. Why even mention it at all.
A typical example would be a couple's text description in a swinger's website or in any other forum where couples are available for swinging and their personal and sexual preferences and details are expressed, such as the example below, this example is just a small part of a typical description of a couple,
He is 178 lbs, HWP, "v"-safe, (also vasectomy safe, or v-safe)....