Gratuitous jokes about penetrations are more Botkin's than Nabokov's style -- and it doesn't have to be "just" that.
Whatever source of the confabulations that come to his mind (whether they come from his fugue or advance from hazel shade), Kinbote is likely to add his personal touch.

Botkin is not likely to know of "Kiss Me, Kate" lyrics (though can come up with "anus" puns on his own, I am sure)

Vanessi leading lady was just too much of a coincidence for me, even without a T.S. Eliot marker.

And a speech in heroic couplets about how breaking customs may be a good thing seems to be a likely nudge to Shade.