If you wanted to get better at making love with women, would you practice making love with men?

You know I almost mentioned that in my original comment but the more I think about it, the more I don't think it's actually bad.

I think a lot of what men might consider "soft skills" in the bedroom (pun intended) would not only transfer to a lesbian context but have more salience there.

Maybe (just for the sake of argument), but does the work make that argument or does it just do whatever it wants and force us to justify it post hoc?

Is this a kind of mistake only male writers make?

Depends what level of meta you're thinking about it on. Female writers make converse mistakes and write e.g. a male character who doesn't care whether he's good in bed, or doesn't even conceptualise that as a metric that one ranks people on.

If you end up asking a woman that, please let me know what she says.