In both men and women, the bulbospongiosus muscles compress attached parts of the erect corpus spongiosum and bulbs of the vestibule and force blood into more distal regions, mainly the glans. In men, the bulbospongiosus muscles have two additional functions:
They facilitate emptying of the bulbous part of the penile urethra following urination (micturition).
Their reflex contraction during ejaculation is responsible for the pulsatile emission of semen from the penis.