Does potassium aluminum sulfate have any effect on sexual performance/sperm counts or anything relating to the functionality of the sexual organs?
Oral ingestion of simple aluminum compounds is not absorbed.  Topical genital application is definitely not recommended.  There is no obvious connection between aluminum and tumescence, one way or another  

Soluble aluminum is toxic, likely cumulatively neurotoxic.  It is not absorbed from the GI tract unless complexed.  Aluminum hydroxide antacids as foaming tablets( citric acid plus sodium bicarbonate) gave aluminum citrate that is bioavailable.  Bad idea.  Pickles are made with alum to keep them ever so crunchy. The soluble aluminum is claimed not to be absorbed. Antiperspirant contains aluminum chlorhydroxide or glycinate to stopper sweat glands.  Topical application is not absorbed.  Exposing mucus membranes to soluble aluminum is definitely not recommended.