A bit more of a hint is given by the second excerpt in The Nabokovian. In this one, we are introduced to a Mr. Hubert (one "m" short of Lolita's Humbert, of course) who seems to be engaged in a Lolita-like relationship with a young girl (presumably the same one as in the first excerpt), here named Flora, of whom we learn little. In the scene, Hubert and Flora play chess with one of those cheap little plastic sets in which the pieces are pegged into holes on the board. There is some sexualizing description of the "tickly-looking little holes [which] ... the pin-sized pawns penetrated easily." And of the young girl who—double entendre warning—"knew the moves." On the relationship of Flora to Laura, though, the passage is mum.
Part one, at Slate, and Part Two. As a Nabokov devotee, and with the classic American authority problem, I can have only one opinion about this -- To hell with the master's wishes, publish the book and sell the original on ebay.
Okay, maybe not ebay.