Being a voice for those who cannot speak for themselves.
Unspayed females typically enter "estrus" or "heat" twice a year. This cycle is characterized by vulvar swelling and physical signs of receptivity to male dogs.
Most pet owners nail the first three. Where we fail, catastrophically, is on numbers four and five.
The specific wording in your query appears to be a unique or non-standard combination of terms rather than a recognized "piece" of official animal classification or anatomical nomenclature.
