haven't been to blacks beach but have visited a couple of the nude beaches in florida (haulover, canaveral seashore [which has another name but brain fart so I don't remember it]). Playalinda (never been there) used to have a big problem with erections and masturbation.
edit: Haulover, have been pulled by several guys in the water (not to orgasm) in the gay section (not gay but a hand is always welcome)......