When I think of a "tomboy", my brain goes to sports, and stereotypically masculine activities. I GUESS that last panel counts, but Rich and I are not on the same page here.
Granted, we share very few pages.
Worth noting is that Larry did not say he was thinking of anyone as dudes. He said he "might as well be talking to a dude", which was mostly just Larry's questionable way of saying he was going to just be himself and act naturally.
It's POSSIBLE Rich has gotten the wrong idea here.