jelqking - Can you describe what you’re doing? I don’t think men can be that discreet when contracting the pelvic muscles to be able to contract one and not the other. The PC muscle is used to pull the rectum up after having a bowel movement. The BC is involved in the force of ejaculation and expelling that last bit of urine when urinating. Contracting or exercising the PC in men doesn’t do much for erections or ejaculation.