It seems to be sensitive to temperature. It is not hard when you erect in winter, but harder when you erect in summer.

In fact, like other animals, it also has estrus, but it is not obvious.

Cat three, dog four, pig five, sheep six, man seven, horse eight.

People's estrus is in July, that is, summer, so your situation can only say that estrus is obvious, which is a normal physiological reaction, so don't worry.