Batman officially does not go down on women because "Heroes don't do that"

In a recent Variety article about recent TV subversions of superhero storytelling, journalist Joe Otterson exposed a curious detail about Batman's cunnilingus habits or rather, lack thereof (emphasis added):

"Harley Quinn" is also unique among the current crop of comic content in that its main character and all of her closest allies are villains rather than heroes in the DC canon.