Show them no mercy and send they stanky ass back to the shower for round 2. Some people just been stanky so long till they don't even know they're in a perpetual state of stankiness. This cuts both ways. I would always request ladies to shower with me before hand even if they don't stank because showering should by default always be part of any healthy session.
Just a PSA
By supervised you mean you watch them wash their ballsack and butt crack three times?