Every young male beach goer needs to know this! When looking at attractive females in bikinis sometimes you get a half chub. Sometimes a raging chub if you haven't recently cranked one out. The trick is you lay stomach down and dig a trench for your Johnson. This will effectively conceal your erection at the beach.
Male 1: "Hey bro, look at these fine as bitties in their bikinis! Its giving me rigor mortis in my pecker."