THIS IS A MEDICAL TERM: IT'S NOT SLANG.
Pariapism is defined as
persistent painful erection of
penis. The disorder is idiopathic in 60% cases while the
remaining 40% of cases are
associated with diseases
(leukaemia, sickle cell disease, pelvic tumours, pelvic
infections), penile trauma and spinal cord injury.
Prolonged sexual stimulation is also said to initiate the
condition. The term pariapism is derived from the name of
the Greek God of fertility, Priapus.
PARIAPISM.