Discharge from the vagina

Question
My older cat is 13 years old, she has been spayed for sometime now for the past week she gets in the mating position and starts discharging a reddish mucous from her vagina. After that she licks herself in a position that I guess she feels comfortable in.  She gets mad when you pet her in that position but does not move.  It doesn't look like she is feeling to good.

Answer
Michael,

The vaginal discharge plus age plus previous spay surgery equals trouble.  It could be something called a stump pyometra, it could be cancer, it could be ovarian remnant, it could be a urinary tract infection, the list goes on and on.  

I recommend getting her to a veterinarian ASAP.  Whatever she has could be life threatening.

Good luck to you both