No, those muscles support your bladder and bowel. They don't have anything to do with blood flow. They are the same muscles you squeeze if you are trying to stop urine flow, or stop a bowel movement (poop).
Here's a decent article on it - https://www.continence.org.au/who-it-affects/men/male-pelvic-floor-muscles It's from Australia, so the spellings are a bit different than the US's or UK's might be.