According to your symptoms it suggests that you have some problem within the bladder such as stone in the bladder or proximal end of the ureter
because you have burning sensation and end urine stream blood(if the pink drops are really the blood). It might not be due to frequent oral sex
but if you had injury
to inner part of the Urethra
also present with burning micturition.
Check for the Kidney stones or Bladder stones by consulting your doctor.
Take care, Dr. Praveen.